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Analytical Ability

মোট প্রশ্ন৬৫৯এই পাতা১০০প্রতি পাতা১০০
প্রশ্ন দেখুনঅনুশীলন
ঘনত্ব
উত্তর
উত্তরিতবর্তমানপুনরায় দেখুনঅসম্পূর্ণ

Analytical Ability

PrepBank · পাতা ৬ / ৭ · ৫০১–৬০০ / ৬৫৯

৫০১.
Which of the following is a leap year? 
  1. ক
    1996
  2. খ
    1982
  3. গ
    2003
  4. ঘ
    2005
ব্যাখ্যা

Question: Which of the following is a leap year?

Solution:
অধিবর্ষ বা লিপ ইয়ার নির্ণয়ের দুটি প্রধান নিয়ম রয়েছে:
১. সাধারণ বছর: বছরটি 4 দ্বারা নিঃশেষে বিভাজ্য হতে হবে।
২. শতাব্দী বছর (100 দ্বারা বিভাজ্য): বছরটি 400 দ্বারা নিঃশেষে বিভাজ্য হতে হবে।

এখন,
1996 ÷ 4 = 499 → নিঃশেষে বিভাজ্য → Leap year।
1982 ÷ 4 = 495.5 → বিভাজ্য নয় → Leap year নয়। 
2003 ÷ 4 = 500.75 → নিঃশেষে বিভাজ্য নয় → Leap year নয়।
2005 ÷ 4 = 501.25 → নিঃশেষে বিভাজ্য নয় → Leap year নয়।

অতএব, 1996 সাল অধিবর্ষ।

৫০২.
Find the minimum number of straight lines required to make the given figure.
  1. ক
    11
  2. খ
    14
  3. গ
    16
  4. ঘ
    17
ব্যাখ্যা
Question: Find the minimum number of straight lines required to make the given figure.

Solution:

Required straight lines: AB, KL, DC, AC, BD, AD, EF, GH, IJ, BC, GK, GL, HK, HL = 14
৫০৩.
In a cash box, there are equal numbers of 10 paisa, 25 paisa and 50 paisa coins. If it contains Tk. 170, then what is the number of 10 paisa coin?
  1. ক
    100
  2. খ
    200
  3. গ
    220
  4. ঘ
    150
ব্যাখ্যা
Question: In a cash box, there are equal numbers of 10 paisa, 25 paisa and 50 paisa coins. If it contains Tk. 170, then what is the number of 10 paisa coin?
 
Solution: 
let, there are x numbers of 10 paisa, 25 paisa and 50 paisa coins.
 
1 tk = 100 paisa 
 
x {(10/100) + (25/100) + (50/100)} = 170 
⇒ x (1/10 + 1/4 + 1/2) = 170 
⇒ 17x/20 = 170 
⇒ x = 200 
৫০৪.
A watch which gains 5 seconds in 3 minutes was set right at 7 a.m. In the afternoon of the same day, when the watch indicated quarter past 4 o'clock, the true time is:
  1. ক
    3 : 59 p.m.
  2. খ
    4 : 00 p.m.
  3. গ
    3 : 58 p.m.
  4. ঘ
    4 : 03 p.m.
ব্যাখ্যা
Question: A watch which gains 5 seconds in 3 minutes was set right at 7 a.m. In the afternoon of the same day, when the watch indicated quarter past 4 o'clock, the true time is:

Solution:
Time from 7 a.m. to 4 : 15 p.m. = 9 hrs 15 min. = 37/4 hrs.
Now,
3 min. 5 sec. of this clock = 3 min. of the correct clock.
⇒ 37/720 hrs. of this clock = 1/20 hrs. of the correct clock.
⇒ 37/4 hrs. of this clock = {(1/20) × (720/37) × (37/4)} hrs. of the correct clock.
= 9 hrs. 

∴ The correct time is 9 hrs. after 7 a.m. =  4 p.m.
৫০৫.
If five students run a mile in 5 minutes, then how much time will 50 students take to run a mile?
  1. ক
    ক) 50 min
  2. খ
    খ) 5 min
  3. গ
    গ) 10 min
  4. ঘ
    ঘ) 250 min
ব্যাখ্যা
Question: If five students run a mile in 5 minutes, then how much time will 50 students take to run a mile?

Solution: 
এখানে দূরত্ব মুখ্য। যেহেতু দূরত্ব দুই ক্ষেত্রেই একই, তবে সময়ও একই লাগবে। 

৫ জন ছাত্রের এক মাইল যেতে সময় লাগে ৫ মিনিট।
৫০ জন ছাত্র যদি একই বেগে দৌড়ায় তবে একসাথে তারা ৫ মিনিটেই ১ মাইল অতিক্রম করে। 
৫০৬.
A student responded to all of the 22 questions on a test and received a score of 63.5. If the scores were derived by adding 3.5 points for each correct answer and deducting 1 point for each incorrect answer, how many questions did the student answer incorrectly?
  1. ক
    3
  2. খ
    4
  3. গ
    15
  4. ঘ
    18
ব্যাখ্যা
Question: A student responded to all of the 22 questions on a test and received a score of 63.5. If the scores were derived by adding 3.5 points for each correct answer and deducting 1 point for each incorrect answer, how many questions did the student answer incorrectly?

Solution:
Let the number of correct answers be X
The number of incorrect answers will be 22 - X
For each correct answer the student got 3.5 points for a total of 3.5X
For each incorrect answer one point was taken out which is equivalent to - (22 - X)
The total he got for that was 63.5

So in short you have the following equation and solution.
3.5X - (22 - X) = 63.5
⇒ 3.5X - 22 + X = 63.5
⇒ 4.5X = 63.5 + 22
⇒ 4.5X = 85.5
⇒ 4.5X/4.5 = 85.5/4.5
∴ X = 19

So incorrect answers will be 22 - X = 22 - 19 = 3.
৫০৭.
Four boys are standing in a line for a photograph. Rifat is to the right of Rafiq. Arif is to the right of Kamal. Kamal is between Rifat and Arif. Rafiq is at the extreme left end. Who is second from the right in the line?
  1. ক
    Kamal
  2. খ
    Rifat
  3. গ
    Arif
  4. ঘ
    Rafiq
ব্যাখ্যা

Question: Four boys are standing in a line for a photograph. Rifat is to the right of Rafiq. Arif is to the right of Kamal. Kamal is between Rifat and Arif. Rafiq is at the extreme left end. Who is second from the right in the line?

Solution:
রিফাত রফিকের ডানদিকে। রফিক ⇔ রিফাত
কামাল, রিফাত এবং আরিফের মাঝে। রিফাত ⇔ কামাল ⇔ আরিফ
রফিক একদম বামপ্রান্তে। রফিক ⇔ রিফাত ⇔ কামাল ⇔ আরিফ
∴ রফিক ⇔ রিফাত ⇔ কামাল ⇔ আরিফ।

∴ কামাল সারিটির ডানদিক থেকে দ্বিতীয় হবে।

৫০৮.
What number will replace the '?' mark?
17, 24, 15, 22, 13, 20, 11, ?
  1. ক
    16
  2. খ
    18
  3. গ
    9
  4. ঘ
    13
ব্যাখ্যা
Question: What number will replace the '?' mark?
17, 24, 15, 22, 13, 20, 11, ?

Solution:
প্রদত্ত সিরিজে ২টি ধারা আছে,
১ম ধারা, 17, 15, 13, 11, ....... অর্থাৎ 2 করে কমছে।
২য় ধার, 24, 22, 20, 18, ....... অর্থাৎ ২ করে কমছে।

∴ সংখ্যা সিরিজের প্রশ্নবোধক চিহ্নের স্থানে 18 বসবে।
৫০৯.
X and Y are the children of Z. Z is the father of X. But Y is not son of Z. What is Y to Z?
  1. ক
    Son and Father
  2. খ
    Nephew and Uncle
  3. গ
    Daughter and Father
  4. ঘ
    Brother and Sister
ব্যাখ্যা
Question: X and Y are the children of Z. Z is the father of X. But Y is not son of Z. What is Y to Z?

Solution: 
Z হচ্ছে X ও Y এর পিতা।
Y, Z এর পুত্রসন্তান নয়।
∴ Y, Z এর কন্যাসন্তান।
৫১০.
An accurate clock shows 10:00 AM. Through how many degrees will the hour hand rotate when the clock shows 4:00 PM?
  1. ক
    90°
  2. খ
    120°
  3. গ
    180°
  4. ঘ
    220°
ব্যাখ্যা

Question: An accurate clock shows 10:00 AM. Through how many degrees will the hour hand rotate when the clock shows 4:00 PM?

Solution: 
10:00 AM থেকে 4:00 PM পর্যন্ত অতিবাহিত সময় = 6 ঘণ্টা।

আমরা জানি,
ঘণ্টার কাঁটা 12 ঘণ্টায় ঘোরে 360°
∴ 1 ঘণ্টায় ঘোরে = 360°/12 = 30°
∴ 6 ঘণ্টায় ঘোরে = 6 × 30° = 180°

অতএব, 10:00 AM থেকে 4:00 PM পর্যন্ত ঘণ্টার কাঁটাটি 180° ঘুরবে

৫১১.
Four girls are sitting on a bench to be photographed. Asma is to the left of Rani. Rubi is to the right of Rani. Rita is between Rani and Rubi. Who would be third from the left in the photograph?
  1. ক
    Rita
  2. খ
    Rani
  3. গ
    Asma
  4. ঘ
    Rubi
ব্যাখ্যা
Question: Four girls are sitting on a bench to be photographed. Asma is to the left of Rani. Rubi is to the right of Rani. Rita is between Rani and Rubi. Who would be third from the left in the photograph?

Solution:
Asma is to the left of Rani.
Asma ⇔ Rani

Rubi is to the right of Rani.
Rani ⇔ Rubi

Rita is between Rani and Rubi.
Rani ⇔ Rita ⇔ Rubi

∴ Asma ⇔ Rani ⇔ Rita ⇔ Rubi.

Rita would be third from the left in the photograph
৫১২.
If PLAY is coded as 8123 and RHYME is coded as 49367, how is MALE coded ?
  1. ক
    ক) 6395
  2. খ
    খ) 6198
  3. গ
    গ) 6217
  4. ঘ
    ঘ) 6285
ব্যাখ্যা
Question: If PLAY is coded as 8123 and RHYME is coded as 49367, how is MALE coded?

Solution: 
এখানে,
P = 8
L = 1
A = 2
Y = 3
R = 4
H = 9
M = 6
E = 7

তাহলে MALE = 6217
৫১৩.
March 20, 1991 was a Wednesday. What day of the week was March 20, 1992? 
  1. ক
    Thursday
  2. খ
    Tuesday
  3. গ
    Friday
  4. ঘ
    Saturday
  5. ঙ
    None of these
ব্যাখ্যা

Question: March 20, 1991 was a Wednesday. What day of the week was March 20, 1992?

Solution:
Given that, 
March 20, 1991 was a Wednesday.

1992 was a leap year which is divisible by 4.
A normal year (non-leap year) has 365 days and 365 ÷ 7 = 52 weeks + 1 day remainder ; day advances by + 1.
A leap year has 366 days and 366 ÷ 7 = 52 weeks + 2 days remainder ; day advances by + 2.

Since the period from March 20, 1991 to March 20, 1992 includes February 29, 1992 (the leap day), it is a full 366-day period.
Therefore Wednesday + 2 days
Wednesday ⇒ Thursday ⇒ Friday

So March 20, 1992 is Friday.

৫১৪.
A ferry can carry 24 buses or 36 cars at a time. If there are 18 buses on the ferry, how many cars can be loaded onto it?
  1. ক
    12
  2. খ
    8
  3. গ
    6
  4. ঘ
    9
ব্যাখ্যা

Question: A ferry can carry 24 buses or 36 cars at a time. If there are 18 buses on the ferry, how many cars can be loaded onto it?

Solution:
Here,
24 buses = 36 cars
∴ 1 bus = 36/24 cars
∴ 18 buses = (36 × 18)/24 cars
= 27 cars

∴ Required number of cars = 36 - 27 = 9 cars

৫১৫.
A clock shows 12 : 00. Through how many degrees has the hour hand moved by 25 minutes past 5? 
  1. ক
    150°
  2. খ
    155°
  3. গ
    160.5°
  4. ঘ
    165°
  5. ঙ
    162.5°
ব্যাখ্যা

Question: A clock shows 12 : 00. Through how many degrees has the hour hand moved by 25 minutes past 5? 

Solution:
Full circle = 360°

Clock has 12 hours; Hour hand moves per hour, 360°/12 = 30° per hour
And, 1 hour = 60 minutes
Hour hand moves per minute = 30°/60 = 0.5° 

Now, 
From 12 : 00 to 5 : 25 = 5 hours 25 minutes = (5 × 60) + 25 = 325 minutes

∴ Degrees moved by hour hand = 325 × 0.5° = 162.5° 

By 25 minutes past 5, the hour hand has moved through 162.5° from the 12 : 00 position.

৫১৬.
On February 5, 1998, it was Thursday. The day of the week on February 5, 1997, was-
  1. ক
    Wednesday
  2. খ
    Monday
  3. গ
    Friday
  4. ঘ
    Sunday
ব্যাখ্যা
Question: On February 5, 1998, it was Thursday. The day of the week on February 5, 1997, was-

Solution:
1997 was an ordinary year, it had 1 odd day. So, the day on February 5, 1998, would be one day beyond the day on February 5, 1997.

∴ Thursday on February 5, 1998, would be one day beyond the day on February 5, 1997, so the day on February 5, 1997, was Wednesday.
৫১৭.
Each of the following questions has a group. Find out which one of the given alternatives will be another member of the group or of that class.
Apple, Grape, Orange
  1. ক
    ক) Vegetable
  2. খ
    খ) Fruits
  3. গ
    গ) Stems
  4. ঘ
    ঘ) Oats
ব্যাখ্যা
Apple, Grape and Orange all these are fruits.
৫১৮.
Shakib's average (arithmetic mean) on 4 tests is 80. What does he need on his fifth test to raise his average to 84?
  1. ক
    102
  2. খ
    100
  3. গ
    96
  4. ঘ
    92
ব্যাখ্যা
Question: Shakib's average (arithmetic mean) on 4 tests is 80. What does he need on his fifth test to raise his average to 84?

Solution:
Total score on 4 tests = 80 × 4 = 320
Total score on 5 tests = 84 × 5 = 420

The score in the fifth test is = 420 - 320
= 100
৫১৯.
In a certain code, LATER = 13579 and CHAIR = 20349, how is CHEAT coded in the language?
  1. ক
    53207
  2. খ
    20735
  3. গ
    70352
  4. ঘ
    25073
ব্যাখ্যা

Question: In a certain code, LATER = 13579 and CHAIR = 20349, how is CHEAT coded in the language?

Solution:
Given that,
L  A  T  E  R
↓   ↓  ↓  ↓   ↓
1   3  5  7  9

and
C  H  A  I  R
↓   ↓   ↓  ↓   ↓
2   0   3  4   9

So
C  H  E  A  T
 ↓  ↓   ↓  ↓  ↓
 2  0   7  3  5

৫২০.
Which number will complete the series:
1, 3, 7, 15, 31, 63, 127, 97, 255, __?
  1. ক
    509
  2. খ
    511
  3. গ
    516
  4. ঘ
    519
ব্যাখ্যা
Question: Which number will complete the series:
1, 3, 7, 15, 31, 63, 127, 97, 255, __?

Solution:
3 - 1 = 2
7 - 3 = 4 = 2 × 2
15 - 7 = 8 = 4 × 2
31 - 15 = 16 = 8 × 2
63 - 31 = 32 = 16 × 2
127 - 63 = 64 = 32 × 2
225 - 97 = 128 = 64 × 2

∴ The next number of 127 will be = (255 + 128 × 2)
= 255 + 256
= 511
৫২১.
Handsome : Beautiful : : Husband : ?
  1. ক
    ক) Women
  2. খ
    খ) Wife
  3. গ
    গ) Girl
  4. ঘ
    ঘ) She
ব্যাখ্যা
Handsome is related to Husband and Beautiful is related to Wife.
৫২২.
What number will replace the '?' mark?
  1. ক
    25
  2. খ
    30
  3. গ
    31
  4. ঘ
    33
ব্যাখ্যা
Question: What number will replace the '?' mark?

Solution:
নিচের ১ম সংখ্যা + নিচের দুই সংখ্যার পার্থক্য = উপরের সংখ্যা।

১ম চিত্রে, 30 + (30 - 15) = 45
তৃতীয় চিত্রে, 28 + (28 - 21) = 35

∴ দ্বিতীয় চিত্রে, 25 + (25 - 19) = 31
৫২৩.
Nobody believes a man who lacks confidence in his ability. None should sit idle and shirk his duty on the plea that it is beyond his power to do without the help of others. Such a man always falls behind. He meets failures and suffers in the long run. So dependence on others is a great curse. The above passage suggests that everyone should possess the virtue of
  1. ক
    ক) punctuality
  2. খ
    খ) dignity
  3. গ
    গ) boldness
  4. ঘ
    ঘ) self-reliance
ব্যাখ্যা
প্রশ্নের মূলকথা হলো,
কেউ এমন মানুষকে বিশ্বাস করে না যার নিজের ক্ষমতার প্রতি আস্থা নেই। যে অন্যের সাহায্য ছাড়া তার দায়িত্ব পালন করতে পারবেনা  ভাবে, তাকে সর্বদাই পিছিয়ে থাকতে হয়। তাকে সবসময় অসফলতা ও ভোগান্তি নিয়ে থাকতে হয়। সুতরাং, পরনির্ভরশীলতা হলো অভিশাপ স্বরূপ।
উল্লিখিত অনুচ্ছেদ থেকে এই পরামর্শ পাওয়া যায় যে, সকলের স্বনির্ভর থাকা জরুরি। 

তাই সঠিক উত্তর হবে self-reliance (স্বনির্ভর)।
৫২৪.
How many times are the hands of a clock at right angle in a day?
  1. ক
    22 times
  2. খ
    44 times
  3. গ
    48 times
  4. ঘ
    24 times
  5. ঙ
    None of these
ব্যাখ্যা

Question: How many times are the hands of a clock at right angle in a day?
 
Solution: 
In 12 hours, they are at right angles 22 times.
∴ In 24 hours, they are at right angles = 2 × 22 = 44 times.

So the hands of a clock are at a right angle 44 times in a day.

৫২৫.
What number will replace the '?' mark? 
8 : 63 :: 10 : ?
  1. ক
    101
  2. খ
    98
  3. গ
    99
  4. ঘ
    100
ব্যাখ্যা
Question: What number will replace the '?' mark? 
8 : 63 :: 10 : ? 

Solution:
এখানে 
8 ⇒ 82 - 1 = 63 
অর্থাৎ 
সম্পর্কটি হলো 
x : x2 - 1 
10 ⇒ 102 - 1 = 99
৫২৬.
According to the following symbol substitutions: '+' means '×', '×' means '-', '-' means '÷', and '÷' means '+', what is the result of 20 + 5 - 10 × 4 ÷ 2?
  1. ক
    10
  2. খ
    8
  3. গ
    6
  4. ঘ
    12
ব্যাখ্যা
Question: According to the following symbol substitutions: '+' means '×', '×' means '-', '-' means '÷', and '÷' means '+', what is the result of 20 + 5 - 10 × 4 ÷ 2?

Solution:
If '+' means '×', '×' means '-', '-' means '÷', and '÷' means '+',

Now,
20 + 5 - 10 × 4 ÷ 2

The transformed expression will be:
20 × 5 ÷ 10 - 4 + 2
= 100 ÷ 10 - 4 + 2
= 10 - 4 + 2
= 6 + 2
= 8
৫২৭.
Today is Sunday. What time will be after 353 days?
  1. ক
    Tuesday
  2. খ
    Wednesday
  3. গ
    Sunday
  4. ঘ
    Monday
ব্যাখ্যা
Question: Today is Friday. What time will be after 353 days?

Solution:
এখানে,
৩৫৩ কে ৭ দিয়ে ভাগ করলে ভাগশেষ থাকে ৩।
৩৫৩ দিন থেকে ৩ দিন বাদ দিলে হয় ৩৫০ দিন।

আমরা জানি,
যে কোনো তারিখ হতে ৭ দিন পর পর (৮ম দিনে) একই বার পাওয়া যায়।
অর্থ্যাৎ, শুক্রবারের ৭ দিন পর বা ৮ম দিনে গিয়ে আবার শুক্রবার পাওয়া যাবে।

অর্থাৎ,
৩৫১ তম দিন রবিবার।
৩৫২ তম দিন সোমবার।
৩৫৩ তম দিন মঙ্গলবার । 
৩৫৪ তম দিন বুধবার।
৫২৮.
What is the reflex angle between the hands of a clock at 9 : 35?
  1. ক
    277.5°
  2. খ
    280°
  3. গ
    282.5°
  4. ঘ
    285°
  5. ঙ
    290°
ব্যাখ্যা

Question: What is the reflex angle between the hands of a clock at 9 : 35?

Solution:
The angle between the hands of the clock is |11M - 60H|°/2
= |(11 × 35) - (60 × 9)|°/2
= |385 - 540|°/2
= |- 155|°/2
= 155°/2
= 77.5°

∴ Reflex angle = 360° - 77.5°
= 282.5°

৫২৯.
How many times are the hands of a clock at right angle in a day?
  1. ক
    22
  2. খ
    24
  3. গ
    44
  4. ঘ
    48
  5. ঙ
    None
ব্যাখ্যা
Question: How many times are the hands of a clock at right angle in a day?

Solution:
In 12 hours, they are at right angles 22 times.
∴ In 24 hours, they are at right angles 44 times.
৫৩০.
An accurate clock shows the time as 3.00. After the hour hand has moved 135°, the time would be- 
  1. ক
    10 : 00
  2. খ
    9 : 30
  3. গ
    7 : 30
  4. ঘ
    5 : 30
ব্যাখ্যা
Question: An accurate clock shows the time as 3.00. After the hour hand has moved 135°, the time would be- 

Solution: 
প্রতি ৫ ঘরের মান ৩০° 

১৩৫° তে ঘন্টার কাঁটা যায় ৪.৫ ঘর 
∴ ৪ ঘন্টা ৩০ মিনিট অতিবাহিত হয়েছে। 

নতুন সময় = ৭ : ৩০ মিনিট 
৫৩১.
A person first moves 8 meters towards north, then 12 meters towards east and finally 8 meters towards north. How far did he go along from the first position?
  1. ক
    ক) 28 m
  2. খ
    খ) 18 m
  3. গ
    গ) 16 m
  4. ঘ
    ঘ) 20 m
ব্যাখ্যা
Question: A person first moves 8 meters towards north, then 12 meters towards east and finally 8 meters towards north. How far did he go along from the first position?

Solution:

DE = EC + CD = 8 + 8 = 16 m 
AD = √(AE2 + DE2) 
= √(122 + 162)
= √(144 + 256)
= √(400)
= 20 m
৫৩২.
If the word NATION is written as OCWMTT, how COUNTRY would be written in that code?
  1. ক
    ক) DOXRYXF
  2. খ
    খ) DQXRYXF
  3. গ
    গ) DPXRYXF
  4. ঘ
    ঘ) DQXRYXE
ব্যাখ্যা
Question: If the word NATION is written as OCWMTT, how COUNTRY would be written in that code?

Solution:

NATION = OCWMTT

Now,

COUNTRY = DQXRYXF
৫৩৩.
Five persons are travelling in a train-A, B. C, D and E. A is the mother of C who is the wife of E. D is the brother of A and B is the husband of A. How is B related to E?
  1. ক
    ক) Bother
  2. খ
    খ) Father
  3. গ
    গ) Uncle
  4. ঘ
    ঘ) Father in Law
ব্যাখ্যা
Question: Five persons are travelling in a train-A, B. C, D and E. A is the mother of C who is the wife of E. D is the brother of A and B is the husband of A. How is B related to E?

Solution: 
A, C এর মা। C,E এর স্ত্রী। 
A, E এর শাশুড়ি। 

D, A এর ভাই। 
B,A এর স্বামী।

∴ B, E এর শ্বশুর।
৫৩৪.
Find out the missing number in the following series.
31, 29, 24, 22, 17, _______
  1. ক
    ক) 15
  2. খ
    খ) 14
  3. গ
    গ) 13
  4. ঘ
    ঘ) 12
ব্যাখ্যা
Question: Find out the missing number in the following series.
31, 29, 24, 22, 17, _______

Solution: 
31 - 2 = 29
29 - 5 = 24
24 - 2 = 22
22 - 5 = 17

অতএব, পরবর্তী সংখ্যা পাওয়ার জন্য 2 বিয়োগ করতে হবে।
∴ পরবর্তী সংখ্যাটি হবে = 17 - 2
= 15
৫৩৫.
Ridoy walked 25 metres towards South. Then he turned to his left and walked 20 metres. He then turned to his left and walked 25 metres. He again turned to his right and walked 15 metres. At what distance is he from the starting point and in which direction?
  1. ক
    35 metres North
  2. খ
    35 metres East
  3. গ
    40 metres East
  4. ঘ
    60 metres East
ব্যাখ্যা
Question: Ridoy walked 25 metres towards South. Then he turned to his left and walked 20 metres. He then turned to his left and walked 25 metres. He again turned to his right and walked 15 metres. At what distance is he from the starting point and in which direction?

Solution:

The movements of Ridoy are as shown in figure.
Ridoy's distance from starting point A = AE = (AD + DE) = (BC + DE) = (20 + 15) m = 35 m.
Also, E is to the East of A.
৫৩৬.
Carpenter, Plumber, Electrician
  1. ক
    ক) Doctor
  2. খ
    খ) Blacksmith
  3. গ
    গ) Professor
  4. ঘ
    ঘ) Lawyer
ব্যাখ্যা
Carpenter, Plumber, Electrician and Blacksmith are in same working category.
৫৩৭.
Six persons A, B, C, D, E, and F are standing in a circle. B is between F and C; A is between E and D; F is to the left of D. Who is between A and C?
  1. ক
    ক) B
  2. খ
    খ) D
  3. গ
    গ) E
  4. ঘ
    ঘ) F
ব্যাখ্যা
Question: Six persons A, B, C, D, E, and F are standing in a circle. B is between F and C; A is between E and D; F is to the left of D. Who is between A and C?

Solution: 
৫৩৮.
How many days are there in n weeks n days?
  1. ক
    8n2
  2. খ
    8n
  3. গ
    14n
  4. ঘ
    8
ব্যাখ্যা
প্রশ্ন: How many days are there in n weeks n days?

সমাধান:  
In one week there are 7 days.
So in n weeks, there are 7n days

∴ total days = 7n + n = 8n
৫৩৯.
Kamal is shorter than Ruhan, but taller than Anika, Dina is shorter than Kamal. Rubayet is shorter than Ruhan but taller than Kamal. Who is tallest in terms of height?
  1. ক
    ক) Kamal
  2. খ
    খ) Ruhan
  3. গ
    গ) Anika
  4. ঘ
    ঘ) Dina
  5. ঙ
    ঙ) Rubayet
ব্যাখ্যা

Question: Kamal is shorter than Ruhan, but taller than Anika, Dina is shorter than Kamal. Rubayet is shorter than Ruhan but taller than Kamal. Who is tallest in terms of height?

Solution:
Kamal is shorter than Ruhan, but taller than Anika.
∴ Ruhan > Kamal > Anika

Dina is shorter than Kamal.
∴ Kamal > Dina

Rubayet is shorter than Ruhan but taller than Kamal.
∴ Ruhan > Rubayet > Kamal.

From all of these relational statement we can say that,
Ruhan is the tallest in terms of height.

৫৪০.
Three different positions of the same dice are shown. Find the number on the face opposite the face showing '2'.
  1. ক
    5
  2. খ
    4
  3. গ
    3
  4. ঘ
    1
ব্যাখ্যা
Question: Three different positions of the same dice are shown. Find the number on the face opposite the face showing '2'.

Solution:
১ম ও ২য় চিত্রে দেখা যায় ২ এর পাশাপাশি আছে ৪, ৫
৩য় চিত্রে দেখা যায় ২ এর পাশাপাশি আছে ৩, ৬

∴ ৩, ৪, ৫, ৬ কোনভাবেই ২ এর বিপরীত পাশে বসবে না। তাই ২ এর বিপরীত পাশে হবে ১।
৫৪১.
Which number can be placed at the sign of interrogation?
  1. ক
    ক) 12
  2. খ
    খ) 16
  3. গ
    গ) 8
  4. ঘ
    ঘ) 4
ব্যাখ্যা
Question: Which number can be placed at the sign of interrogation?


Solution: 
6 × 5 × 4 = 120
6 × 7 × 3 = 126

ধরি, প্রশ্নবোধক স্থানে x বসবে। 

8 × 5 × x = 320 
⇒ 40 × x = 320 
∴ x = 320/40
= 8
৫৪২.
In a certain language PENSION is coded as NEISNOP, how is COLLEGE coded in that code?
  1. ক
    EOELLGC
  2. খ
    EEOLLGC
  3. গ
    EOLELGC
  4. ঘ
    None of these
ব্যাখ্যা
Question: In a certain language PENSION is coded as NEISNOP, how is COLLEGE coded in that code?

Solution: 
PENSION ⇔ NEISNOP
P ⇒ E ⇒ N ⇒ S ⇒ I ⇒ O ⇒ N 
1 ⇒ 2 ⇒ 3 ⇒ 4 ⇒ 5 ⇒ 6 ⇒ 7
N ⇒ E ⇒ I ⇒ S ⇒ N⇒ O ⇒ P
Here,
Letters of 1st and 7th position inter-change their position.
Letters of 3rd and 5th position also inter-change their position.
And the letters of even number position remain same.

C ⇒ O ⇒ L ⇒ L ⇒ E ⇒ G ⇒ E 
1 ⇒ 2 ⇒ 3 ⇒ 4 ⇒ 5 ⇒ 6 ⇒ 7
E ⇒ O ⇒ E ⇒ L ⇒ L ⇒ G ⇒ C

∴ COLLEGE ⇔ EOELLGC
৫৪৩.
Today is Wednesday. After 86 days, what day of the week will it be?
  1. ক
    Friday
  2. খ
    Tuesday
  3. গ
    Wednesday
  4. ঘ
    Thursday
ব্যাখ্যা

Question: Today is Wednesday. After 86 days, what day of the week will it be?

Solution:
Each day of the week is repeated after 7 days.

So, after (7 × 12) = 84 days, it will be Wednesday.

After 85 days, it will be Thursday
After 86 days, it will be Friday.

∴ After 86 days, it will be Friday.

৫৪৪.
In a class of 35 students, Rajib is placed seventh from the bottom whereas Karim is placed ninth from the top. Dipa is placed exactly in between the two. What is the difference in the positions of Rajib and Dipa?
  1. ক
    9
  2. খ
    10
  3. গ
    11
  4. ঘ
    13
ব্যাখ্যা
Question: In a class of 35 students, Rajib is placed seventh from the bottom whereas Karim is placed ninth from the top. Dipa is placed exactly in between the two. What is the difference in the positions of Rajib and Dipa?

Solution:
Total students = 35
Rajib is 7th from bottom, Karim is 9th from top and Dipa is exactly between Karim and Rajib

We know,
n position from bottom = (Total + 1 - n) position from top

Rajib's position = 7th from bottom = (35 + 1 - 7)th from top = 29th from top
Karim's position = 9th from top

Dipa is placed exactly in between Rajan and Karan.
Total students between Karim and Rajib = 35 - (9 + 7) = 35 - 16 = 19
Thus, Dipa's position from Karim = (19 + 1)/2 = 20/2 = 10
Dipa's position from top = 9 + 10 = 19,

Hence, differences in the positions of Rajib and Dipa = 29 - 19 = 10 i.e total 10 seats.
৫৪৫.
A clock seen through a mirror, shows quarter past five. What is the correct time shown by the clock? 
  1. ক
    5 : 45
  2. খ
    7 : 25
  3. গ
    4 : 25
  4. ঘ
    None of these
ব্যাখ্যা

Question: A clock seen through a mirror, shows quarter past five. What is the correct time shown by the clock?

Solution:
Quarter past five = 5 : 15

আমরা জানি,
প্রকৃত সময় = 11 : 60 - আয়নার দেখা সময়
= 11 : 60 - 5 : 15
= 6 : 45

৫৪৬.
What will come at the place of question mark? 6, 11, 21, 36, 56, ?
  1. ক
    76
  2. খ
    81
  3. গ
    86
  4. ঘ
    91
ব্যাখ্যা

Question: What will come at the place of question mark?
6, 11, 21, 36, 56, ?

Solution:
11 - 6 = 5
21 - 11 = 10
36 - 21 = 15
56 - 36 = 20

প্রতিবার পার্থক্য 5 করে বৃদ্ধি পাচ্ছে।

∴ পরবর্তী পার্থক্য হবে = 20 + 5 = 25

∴ পরবর্তী সংখ্যা = 56 + 25 = 81

Shortcut: 6 (+5)→ 11 (+10)→ 21 (+15)→ 36 (+20)→ 56 (+25) → 81.

৫৪৭.
Some months have 30 days and some have 31. How many months have at least 28 days? 
  1. ক
    12
  2. খ
    1
  3. গ
    10
  4. ঘ
    3
  5. ঙ
    5
ব্যাখ্যা

Question: Some months have 30 days and some have 31. How many months have at least 28 days? 

Solution:
Every month has at least 28 days. [February has 28 days in a common year and 29 in a leap year].

We know,
January, March, May, July, August, October, December is 31 days
April, June, September, November is 30 days
And February is 28 or 29 days

So all 12 months have at least 28 days.

৫৪৮.
There are 120 chickens and goats on a farm. There are 70 more chickens than goats. How many goats are there?
  1. ক
    25
  2. খ
    30
  3. গ
    45
  4. ঘ
    50
ব্যাখ্যা
Question: There are 120 chickens and goats on a farm. There are 70 more chickens than goats. How many goats are there?

Solution:
Let,
The number of goats be x
∴ The number of chickens x + 70

ATQ,
x + x + 70 = 120
⇒ 2x = 50
∴ x = 25
৫৪৯.
Which of the following is a leap year?
  1. ক
    1900
  2. খ
    2000
  3. গ
    2022
  4. ঘ
    2010 
ব্যাখ্যা

Question: Which of the following is a leap year?

Solution:
অধিবর্ষ বা লিপ ইয়ার নির্ণয়ের দুটি প্রধান নিয়ম রয়েছে:
১. সাধারণ বছর: বছরটি 4 দ্বারা নিঃশেষে বিভাজ্য হতে হবে।
২. শতাব্দী বছর (100 দ্বারা বিভাজ্য): বছরটি 400 দ্বারা নিঃশেষে বিভাজ্য হতে হবে।

এখন,
ক) 1900 সাল (শতাব্দী বছর): 1900 ÷ 400 দ্বারা বিভাজ্য নয় (ভাগশেষ 300)। ⇒ অধিবর্ষ নয়।

খ) 2000 সাল (শতাব্দী বছর): 2000 ÷ 400 = 5 (ভাগশেষ 0)। ⇒ অধিবর্ষ।

গ) 2022 সাল: এটি 4 দ্বারা বিভাজ্য নয়। (2022 ÷ 4 ⇒ ভাগশেষ 2)। ⇒ অধিবর্ষ নয়।

ঘ) 2010 সাল: এটি 4 দ্বারা বিভাজ্য নয়। (2010 ÷ 4 ⇒ ভাগশেষ 2)। ⇒ অধিবর্ষ নয়।

অতএব, 2000 সালটি অধিবর্ষ।

৫৫০.
Today is Friday. After 61 days, it will be:
  1. ক
    Saturday
  2. খ
    Sunday
  3. গ
    Tuesday
  4. ঘ
    Wednesday
  5. ঙ
    None
ব্যাখ্যা
Question: Today is Friday. After 61 days, it will be:

Solution:
Each day of the week is repeated after 7 days.
So, after 63 days, it will be Friday.
After 62 days, it will be Thursday.
∴ After 61 days, it will be Wednesday.
৫৫১.
What is the angle between the hour and minute hands of a clock when it is 4 : 20 pm?
  1. ক
    7.5°
  2. খ
    6.5°
  3. গ
    8°
  4. ঘ
    10°
ব্যাখ্যা

Question: What is the angle between the hour and minute hands of a clock when it is 4 : 20 pm?

Solution:
4টা 20 মিনিট = 4 + (20/60) ঘন্টা
= 4 + 1/3
= 13/3 ঘন্টা

আমরা জানি,
ঘণ্টার কাঁটা 12 ঘণ্টায় 360° ঘোরে।
∴ 1 ঘণ্টায় ঘোরে = 360°/12 = 30°
∴ 13/3 ঘণ্টায় ঘোরে = (30° × 13)/3
= 390°/3
= 130°

আবার,
মিনিটের কাঁটা 60 মিনিটে 360° ঘোরে।
∴ 1 মিনিটে ঘোরে = 360°/60 = 6°
∴ 20 মিনিটে ঘোরে = 20 × 6° = 120°

∴ ঘড়ির কাঁটা দুটির মধ্যবর্তী কোণ = | 130° - 120° |
= 10°

৫৫২.
Six friends are sitting in a circle facing inwards. Priti and Ashwini are exactly opposite to each other. Sachin is in between Priti and Dipen. Dipen is immediately to the left of Ashwini. Rishi is not exactly opposite to Dipen. Who is just right to Ashwini?
  1. ক
    Rupesh
  2. খ
    Ashwini
  3. গ
    Rishi
  4. ঘ
    Sachin
ব্যাখ্যা

Question: Six friends are sitting in a circle facing inwards. Priti and Ashwini are exactly opposite to each other. Sachin is in between Priti and Dipen. Dipen is immediately to the left of Ashwini. Rishi is not exactly opposite to Dipen. Who is just right to Ashwini?

Solution:

So, Rishi is just right to Ashwini.

৫৫৩.
An accurate clock shows the time as 3.00. After the hour hand has moved 135°, the time would be- 
  1. ক
    5 : 30
  2. খ
    7 : 30
  3. গ
    9 : 30
  4. ঘ
    10 : 00
ব্যাখ্যা

Question: An accurate clock shows the time as 3.00. After the hour hand has moved 135°, the time would be- 

Solution: 
প্রতি ৫ ঘরের মান ৩০° 

১৩৫° তে ঘন্টার কাঁটা যায় ৪.৫ ঘর 
∴ ৪ ঘন্টা ৩০ মিনিট অতিবাহিত হয়েছে। 

নতুন সময় = ৭ : ৩০ মিনিট 

৫৫৪.
0.15, 0.3, ____, 1.2, 2.4. What number should fill the blank?
  1. ক
    0.6
  2. খ
    0.9
  3. গ
    0.006
  4. ঘ
    4.8
ব্যাখ্যা

Question: 0.15, 0.3, ____, 1.2, 2.4. What number should fill the blank?
 
Solution:
Each term is being multiplied by 2,

Now,
0.15 × 2 = 0.3  
0.3 × 2 = 0.6  
0.6 × 2 = 1.2  
1.2 × 2 = 2.4

So the complete series is-
0.15, 0.3, 0.6, 1.2, 2.4

∴ Blank should be filled with 0.6

৫৫৫.
Find the number of triangles in the given figure.
  1. ক
    16
  2. খ
    18
  3. গ
    20
  4. ঘ
    21
ব্যাখ্যা
Question: Find the number of triangles in the given figure.


Solution:

The simplest triangles are = EFH, BIC, GHJ, GIJ, EKD and CKD = 6 in number
The triangles composed of two components each are = ABJ, AFJ, GCK, GEK, CED arid GHI = 6 in number
The triangles composed of three components each are = GCD, GED, DJB and DJF = 4 in number.
The triangles composed of four components each are = ABF and GCE = 2 in number.
The triangles composed of five components each are = ABD and AFD = 2 in number.
There is only one triangle = FBD composed of six components.

∴ Total number of triangles in the figure = 6 + 6 + 4 + 2 + 2 + 1 = 21.
৫৫৬.
How many triangles are there in the following figure.
  1. ক
    17
  2. খ
    19
  3. গ
    20
  4. ঘ
    21
ব্যাখ্যা
Question: How many triangles are there in the following figure.

Solution:

△AEF, △BEP, △EOP, △BPD, △OPD, △ODQ, △OQF, △CFQ, △CDQ, △BEO, △BED, △BOD, △DEO, △CFO, △CDO, △CFD, △DFO, △BCO, △DEF and △ABC
There are 20 triangles.
৫৫৭.
A clock gains (moves ahead) 10 minutes each day. How many days will it take to reach a point where the clock will indicate the correct time?
  1. ক
    36 days
  2. খ
    54 days
  3. গ
    72 days
  4. ঘ
    80 days
ব্যাখ্যা

Question: A clock gains (moves ahead) 10 minutes each day. How many days will it take to reach a point where the clock will indicate the correct time?

Solution:
একটি ঘড়িকে পুনরায় সঠিক সময় দেখাতে হলে তাকে 12 ঘণ্টা সময় এগিয়ে যেতে হবে।
কারণ একটি 12 ঘণ্টার ঘড়িতে যখন সঠিক সময় থেকে 12 ঘণ্টা এগিয়ে যাবে, তখন এটি আবার সঠিক সময় নির্দেশ করবে।

12 ঘণ্টা = 12 × 60 মিনিট = 720 মিনিট

এখন, যেহেতু ঘড়িটি প্রতিদিন 10 মিনিট করে সময় এগিয়ে যায়,

10 মিনিট সময় এগিয়ে যায় 1 দিনে
∴ 720 মিনিট সময় এগিয়ে যাবে = (1/10) × 720 দিনে
= 72 দিনে

সুতরাং, 72 দিন পর ঘড়িটি আবার সঠিক সময় দেখাবে।

৫৫৮.
Arrange the following numbers in ascending order: 105, 78, 92, 64, 119, 50, 83
  1. ক
    50, 64, 78, 83, 92, 105, 119
  2. খ
    64, 50, 78, 83, 105, 92, 119
  3. গ
    119, 105, 92, 83, 78, 64, 50
  4. ঘ
    78, 83, 50, 64, 92, 105, 119 
ব্যাখ্যা

Question: Arrange the following numbers in ascending order: 105, 78, 92, 64, 119, 50, 83 

Solution: 
Given the series, 
105, 78, 92, 64, 119, 50, 83

Now, 
Ascending order(ছোট থেকে বড়)
50, 64, 78, 83, 92, 105, 119

৫৫৯.
In a certain code language COMPUTER is written as RFUVQNPC. How will BRAVE be written in that code language?
  1. ক
    ETSNR
  2. খ
    EWBSB
  3. গ
    CTWNB
  4. ঘ
    ETQNB
ব্যাখ্যা
Question: In a certain code language COMPUTER is written as RFUVQNPC. How will BRAVE be written in that code language?

Solution:
Rewrite the word in reverse order ⇒ COMPUTER = RETUPMOC
simply replace the remaining letters in alphabetical order such that: E = F, T = U, U = V, P = Q, M = N, O = P [Without 1st and last letter]
we get, COMPUTER = RFUVQNPC

Similarly, BRAVE = EVARB
now, V = W, A = B, R = S [Without 1st and last letter]
∴ BRAVE = EWBSB
৫৬০.
If the word CLEAR is written as 90847 and SEARP is written as 58476. Find the code for RESALE-
  1. ক
    586048
  2. খ
    450875
  3. গ
    587490
  4. ঘ
    785408
ব্যাখ্যা
Question: If the word CLEAR is written as 90847 and SEARP is written as 58476. Find the code for RESALE-

Solution:
Given,
C = 9 
L = 0
E = 8
A = 4
R = 7

and,
S = 5
E = 8
A = 4
R = 7
P = 6

Similarly,
R = 7
E = 8
S = 5
A = 4
L = 0
E = 8
৫৬১.
Raitul walked 55 metres towards South. Then he turned to his left and walked 45 metres. He then turned to his left and walked 55 metres. He again turned to his right and walked 40 metres. At what distance is he from the starting point and in which direction?
  1. ক
    60 metres East
  2. খ
    58 metres East
  3. গ
    65 metres North
  4. ঘ
    85 metres East
ব্যাখ্যা
Question: Raitul walked 55 metres towards South. Then he turned to his left and walked 45 metres. He then turned to his left and walked 55 metres. He again turned to his right and walked 40 metres. At what distance is he from the starting point and in which direction?

Solution:

The movements of Raitul are as shown in figure.
Raitul's distance from starting point A to end point E = AE = (AD + DE) = (BC + DE) = (45 + 40) m = 85 m.
Also, E is to the East of A.
৫৬২.
Which one of the following figure is different from the rest three?
  1. ক
    ক)
  2. খ
    খ)
  3. গ
    গ)
  4. ঘ
    ঘ)
ব্যাখ্যা
প্রশ্ন: Which one of the following figure is different from the rest three?




সমাধান: 
সবগুলো চিত্র আড়াআড়ি (×) দাগ দ্বারা ৪ ভাগে বিভক্ত হয়েছে, কেবলমাত্র গ বা ৩ নং চিত্র ছাড়া।
তাই, গ এর চিত্রটি ভিন্ন। 
৫৬৩.
A certain culture of bacteria quadruples every hour. If a container with these bacteria was half full at 10:00 a.m., at what time was it one-eighth full?
  1. ক
    9:00 a.m.
  2. খ
    7:00 a.m.
  3. গ
    6:00 a.m.
  4. ঘ
    4:00 a.m.
ব্যাখ্যা
Question: A certain culture of bacteria quadruples every hour. If a container with these bacteria was half full at 10:00 a.m., at what time was it one-eighth full?

Solution:
To go from one-eighth (1/8) full to half (1/2) full culture of bacteria should quadruple: (1/2) ÷ (1/8) = (1/2) × 8 = 4
As it quadruples every hour then container was one-eighth full at 10:00 a.m - 1 hour = 9:00 a.m.
৫৬৪.
What number should come next in the series:
5, 7, 13, 31, 85,.......?
  1. ক
    217
  2. খ
    247
  3. গ
    271
  4. ঘ
    284
ব্যাখ্যা

Question: What number should come next in the series:
5, 7, 13, 31, 85,.......?

Solution:
দেওয়া আছে,
সিরিজটি হলো: 5, 7, 13, 31, 85,.......

পার্থক্যগুলোর মধ্যে একটি প্যাটার্ন রয়েছে। প্রতিটি পার্থক্য আগের পার্থক্যের 3 গুণ।

5 থেকে 7 পর্যন্ত পার্থক্য: 2
7 থেকে 13 পর্যন্ত পার্থক্য: 6 (2 × 3)
13 থেকে 31 পর্যন্ত পার্থক্য: 18 (6 × 3)
31 থেকে 85 পর্যন্ত পার্থক্য: 54 (18 × 3)

সুতরাং, পরবর্তী পার্থক্যটি হবে:
54 × 3 = 162

পরবর্তী সংখ্যাটি হবে শেষ সংখ্যা এবং এই পার্থক্যের যোগফল:
85 + 162 = 247
∴ পরবর্তী সংখ্যাটি হলো 247

৫৬৫.
What will replace the '?' mark?
 
  1. ক
    60
  2. খ
    70
  3. গ
    85
  4. ঘ
    100
ব্যাখ্যা

Question: What will replace the '?' mark?

Solution:
এখানে, উপরের সংখ্যাটি নিচের দুটি সংখ্যার যোগফলের দ্বিগুণ।

১ম চিত্রে,
(15 + 10) × 2 = 25 × 2 = 50

২য় চিত্রে,
(30 + 15) × 2 = 45 × 2 = 90

একইভাবে, ৩য় চিত্রে,
(25 + 10) × 2 = 35 × 2 = 70

সুতরাং, সঠিক উত্তরটি হবে 70।

৫৬৬.
If SINGLE = 66, Then DOUBLE =? 
  1. ক
    59
  2. খ
    33
  3. গ
    60
  4. ঘ
    132
ব্যাখ্যা
Question: If SINGLE = 66, Then DOUBLE =? 

Solution:

S + I + N + G + L + E 
19 + 9 + 14 + 7 + 12 + 5
= 66

Now,
D + O + U + B + L + E
4 + 15 + 21 + 2 + 12 + 5
= 59
৫৬৭.
If A = 3, B = 5, C = 7, and so on, what is the meaning of the following numbers 39, 29, 3, 19, 25?
  1. ক
    SNAKE
  2. খ
    TIGER
  3. গ
    SMILE
  4. ঘ
    SNAIL
ব্যাখ্যা

Question: If A = 3, B = 5, C = 7, and so on, what is the meaning of the following numbers 39, 29, 3, 19, 25?

Solution:
Given,
A = 3, B = 5, C = 7, .....
∴ প্রতিটি কোড = (অক্ষরের অবস্থান × 2) + 1

So,
(39 - 1)/2 = 19 → S
(29 - 1)/2 = 14 → N
(3 - 1)/2 = 1 → A
(19 - 1)/2 = 9 → I
(25 - 1)/2 = 12 → L

∴ The meaning of the following number = SNAIL

৫৬৮.
The angle between the minute hand and the hour hand of a clock when the time is 8 : 30 is:
  1. ক
    80°
  2. খ
    75°
  3. গ
    60°
  4. ঘ
    105°
ব্যাখ্যা
Question: The angle between the minute hand and the hour hand of a clock when the time is 8 : 30 is:

Solution:
= │(11m - 60h)/2│°
= │(11 × 30 -  60 × 8)/2│°
= │(330 - 480)/2│°
= │- 150/2│°
= 75°
৫৬৯.
Sunrise : Sunset-
  1. ক
    ক) Dawn : Twilight
  2. খ
    খ) Noon : Midnight
  3. গ
    গ) Morning : Night
  4. ঘ
    ঘ) Energetic : Lazy
ব্যাখ্যা
At sunrise morning begins, similarly at sunset night begins.
৫৭০.
It is possible for which of the following groups of crops to grow together in field 2-
  1. ক
    ক) F, G, and H
  2. খ
    খ) F, H, and I
  3. গ
    গ) G, H, and J
  4. ঘ
    ঘ) G, I, and J
ব্যাখ্যা
Question: It is possible for which of the following groups of crops to grow together in field 2-

Solution: 
G, H, I, J ফিল্ড ২ তে উৎপাদন করা যেতে পারে। 
J, H একই ফিল্ডে উৎপাদন করা যায় না। 

অতএব একসাথে ফিল্ড ২ এ উৎপাদন করা যাবে GHI অথবা GIJ.
৫৭১.
If p × q = p + q +p/q, then the value of 8 × 2 is?
  1. ক
    6
  2. খ
    10
  3. গ
    14
  4. ঘ
    16
ব্যাখ্যা
Question: If p × q = p + q +p/q, then the value of 8 × 2 is?

Solution:
দেওয়া আছে,
p × q = p + q +p/q

∴ 8 × 2 = 8 + 2 + 8/2
= 10 + 4
= 14
৫৭২.
It was Friday on January 1, 2016. What was the day of the week on Jan 1, 2017?
  1. ক
    Saturday
  2. খ
    Friday
  3. গ
    Tuesday
  4. ঘ
    Sunday
ব্যাখ্যা

Question: It was Friday on January 1, 2016. What was the day of the week on Jan 1, 2017?

Solution:
• অধিবর্ষ নির্ণয়:
2016 সালটি 4 দ্বারা বিভাজ্য (2016 ÷ 4 = 504), তাই এটি একটি অধিবর্ষ (Leap Year)।

• অতিরিক্ত দিন নির্ণয়:
একটি অধিবর্ষে 366 দিন থাকে। 366 ÷ 7 = 52 সপ্তাহ এবং 2 দিন অতিরিক্ত (Odd Days) হয়।

এখন,
1লা জানুয়ারি 2016 দিনটি ছিল Friday।
যেহেতু 2016 সালটি অধিবর্ষ, তাই 1লা জানুয়ারি 2017 দিনটি হবে Friday এর থেকে 2 দিন বেশি।
⇒ Friday + 1 দিন = Saturday
⇒ Saturday + 1 দিন = Sunday

∴ 1লা জানুয়ারি 2017 দিনটি হবে Sunday।

৫৭৩.
In a certain code 'TABLE' is written as WDEOH. How would 'SKY' be written in that code?
  1. ক
    BNY
  2. খ
    NYB
  3. গ
    TBN
  4. ঘ
    VNB
ব্যাখ্যা
Question: In a certain code 'TABLE' is written as WDEOH. How would 'SKY' be written in that code?

Solution:

TABLE is written as WDEOH 
Here each letter is replaced by the third letter after it.
এখানে প্রতিটি বর্ণ তার পরের তৃতীয় বর্ণ দ্বারা প্রতিস্থাপিত হচ্ছে।

∴ SKY is written as VNB.
৫৭৪.
Which of the following is a leap year?
  1. ক
    1982
  2. খ
    1984
  3. গ
    1998
  4. ঘ
    2002
ব্যাখ্যা

Question: Which of the following is a leap year?

Solution:
অধিবর্ষ বা লিপ ইয়ার নির্ণয়ের দুটি প্রধান নিয়ম রয়েছে:
১. সাধারণ বছর: বছরটি 4 দ্বারা নিঃশেষে বিভাজ্য হতে হবে।
২. শতাব্দী বছর (100 দ্বারা বিভাজ্য): বছরটি 400 দ্বারা নিঃশেষে বিভাজ্য হতে হবে।

এখন,
1982 ÷ 4 = 495.5 → বিভাজ্য নয় → Leap year নয়। 
1984 ÷ 4 = 496 → বিভাজ্য → Leap year. 
1998 ÷ 4 = 499.5 → বিভাজ্য নয় → Leap year নয়। 
2002 ÷ 4 = 500.5 → বিভাজ্য নয় → Leap year নয়। 

অতএব, 1984 সালটি অধিবর্ষ।

৫৭৫.
If Z = 52 and BAT = 46, then RAT will be equal to-
  1. ক
    78 
  2. খ
    36
  3. গ
    24
  4. ঘ
    120
ব্যাখ্যা
Question: If Z = 52 and BAT = 46, then RAT will be equal to-

Solution:

Here,
The Position number of Z is 26 which is re-write as 26 × 2 = 52.
Now,
BAT = (2 × 2) + (1 × 2) + (20 × 2) 
= 4 + 2 + 40
= 46

Similarly,
RAT = (18 × 2) + (1 × 2) + (20 × 2)
= 36 + 2 + 40
= 78
৫৭৬.
Alif is shorter than Meena but taller than Zara. Pial is taller than Alif. Meena is the second-tallest person among them. Sumon is shorter than Zara. Who is the third-tallest person among them?
  1. ক
    Alif
  2. খ
    Pial
  3. গ
    Meena
  4. ঘ
    Zara
ব্যাখ্যা

Question: Alif is shorter than Meena but taller than Zara. Pial is taller than Alif. Meena is the second-tallest person among them. Sumon is shorter than Zara. Who is the third-tallest person among them?

Solution:
First statement: Meena > Alif > Zara

Second statement: Pial > Alif

Third statement: Meena is the second-tallest, meaning one person is taller than Meena. Since Pial is taller than Alif and Meena is taller than Alif, Pial must be taller than Meena.
Therefore, Pial > Meena > Alif

Fourth statement: Zara > Sumon

Putting everyone together: Pial > Meena > Alif > Zara > Sumon

∴ The third-tallest person is Alif.

৫৭৭.
A cube of side 5 cm is painted on all its side. If it is sliced into 1 cubic centimer cubes, how many 1 cubic centimeter cubes will have exactly one of their sides painted?
  1. ক
    98
  2. খ
    61
  3. গ
    54
  4. ঘ
    9
ব্যাখ্যা
Question: A cube of side 5 cm is painted on all its side. If it is sliced into 1 cubic centimer cubes, how many 1 cubic centimeter cubes will have exactly one of their sides painted?

Solution:
When a 5 cubic centimeter cube is sliced into 1 cubic centimeter cubes, we will get 5 × 5 × 5 = 125 cubes of 1 cubic centimeter.

In each side of the larger cube, the smaller cubes on the edges will have more than one of their sides painted.
Therefore, the cubes which are not on the edge of the larger cube and that lie on the facing sides of the larger cube will have exactly one side painted.

In each face of the larger cube, there will be 5 × 5 = 25 cubes.
Of these, the cubes on the outer rows will be on the edge. 16 such cubes exist on each face.
If we count out the two outer rows on either side of a face of the cube, we will be left with 3 × 3 = 9 cubes which are not on the edge in each face of the cube.

Therefore, there will be 9 cubes of 1-cc volume per face that will have exactly one of their sides painted.
In total, there will be 9 × 6 = 54 such cubes.
৫৭৮.
Which of the following fractions has the smallest value?
  1. ক
    ক) 8/7
  2. খ
    খ) 10/9
  3. গ
    গ) 21/20
  4. ঘ
    ঘ) 41/40
  5. ঙ
    ঙ) 1013/1012
ব্যাখ্যা
Question: Which of the following fractions has the smallest value?

Solution:
8/7 = 1.14285
10/9 = 1.11111
21/20 = 1.05
41/40 = 1.025
1013/1012 = 1.000988

∴ The Smallest value of given fractions is 1013/1012
৫৭৯.
Which number will complete the series :
0, 1, 4, 15, ?, 325, 1956
  1. ক
    60
  2. খ
    64
  3. গ
    75
  4. ঘ
    80
ব্যাখ্যা
Question: Which number will complete the series :
0, 1, 4, 15, ?, 325, 1956

Solution:
0
0 × 1 + 1 = 1
1 × 2 + 2 = 4
4 × 3 + 3 = 15
15 × 4 + 4 = 64
64 × 5 + 5 = 325
325 × 6 + 6 = 1956
৫৮০.
Which of the following is not similar to others?
  1. ক
    Mitigate
  2. খ
    Alleviate
  3. গ
    Attenuate
  4. ঘ
    Aggravate
ব্যাখ্যা
এখানে,
mitigate, alleviate, attenuate সমার্থক শব্দ যাদের অর্থ হল কমানো বা হ্রাস করা বা উপশম করা।

কিন্তু, 
Aggravate শব্দের অর্থ বৃদ্ধি করা বা উত্তেজিত করা।
৫৮১.
A clock loses (falls behind) 15 minutes each day. How many days will it take to reach a point where the clock will indicate the correct time?
  1. ক
    36 days
  2. খ
    48 days
  3. গ
    54 days
  4. ঘ
    72 days
ব্যাখ্যা

Question: A clock loses (falls behind) 15 minutes each day. How many days will it take to reach a point where the clock will indicate the correct time?

Solution:
একটি ঘড়িকে পুনরায় সঠিক সময় দেখাতে হলে তাকে 12 ঘণ্টা সময় হারাতে হবে। কারণ একটি 12 ঘণ্টার ঘড়িতে যখন সঠিক সময় থেকে 12 ঘণ্টা সময় পিছিয়ে পড়বে, তখন এটি আবার সঠিক সময় নির্দেশ করবে।
12 ঘণ্টা = 12 × 60 মিনিট = 720 মিনিট

এখন, যেহেতু ঘড়িটি প্রতিদিন 15 মিনিট করে সময় হারায়,

15 মিনিট সময় হারায় 1 দিনে
∴720 মিনিট সময় হারাবে = (1/15) × 720 দিনে
= 48 দিনে
সুতরাং, 48 দিন পর ঘড়িটি আবার সঠিক সময় দেখাবে।

৫৮২.
What will come at the place of question mark?
3, 6, 11, 18, 27, ?
  1. ক
    48
  2. খ
    41
  3. গ
    36
  4. ঘ
    43
  5. ঙ
    38
ব্যাখ্যা

Question: What will come at the place of question mark?
3, 6, 11, 18, 27, ?

Solution:
Look at the differences between consecutive terms.
6 - 3 = 3
11 - 6 = 5
18 - 11 = 7
27 - 18 = 9
The first differences are 3, 5, 7, 9
These increase by + 2 each time (3 ⇒ 5 ⇒ 7 ⇒ 9).
So the next difference should be = 9 + 2 = 11

Therefore next number = 27 + 11 = 38

৫৮৩.
Six people Nitro, Nemesis, Nick Fury, Viper, Kronos and Hulk are attending a hexagonal table conference. All the sides of the hexagon table so formed are of same length. Nitro is not adjacent to Nemesis or Nick Fury, Viper is not adjacent to Nick Fury or Kronos. Nemesis and Nick Fury are adjacent, Hulk is in the middle of Viper and Nick Fury. Who is placed exactly opposite to Kronos?
  1. ক
    Nemesis
  2. খ
    Nick Fury
  3. গ
    Viper
  4. ঘ
    Hulk
ব্যাখ্যা
Question: Six people Nitro, Nemesis, Nick Fury, Viper, Kronos and Hulk are attending a hexagonal table conference. All the sides of the hexagon table so formed are of same length. Nitro is not adjacent to Nemesis or Nick Fury, Viper is not adjacent to Nick Fury or Kronos. Nemesis and Nick Fury are adjacent, Hulk is in the middle of Viper and Nick Fury. Who is placed exactly opposite to Kronos?

Solution:
Hulk is in the middle of Viper and Nick Fury.
Nemesis and Nick Fury are adjacent.
Nitro is not adjacent to Nick Fury.

Thus, two arrangements are possible.

Hulk is exactly opposite to Kronos.
৫৮৪.
It is impossible for the earth to
  1. ক
    move round the sun
  2. খ
    have lights on it
  3. গ
    be the most important planet of the solar system
  4. ঘ
    be the nearest planet of the sun
ব্যাখ্যা
অপশন ক) পৃথিবী সর্বদা সূর্যের চার দিকে ঘুরে। সুতরাং, ক অসম্ভব হতে পারে না। 

অপশন খ) have something on এর অর্থ হচ্ছে- বস্তুর উপরে কোন কিছু পড়া। পৃথিবীর নিজস্ব আলো নেই। তবে পৃথিবীর উপর সূর্য থেকে আলো পড়ে। সুতরাং, খ অসম্ভব হতে পারে না।

অপশন গ) পৃথিবী একমাত্র গ্রহ যা প্রাণীর বসবাস উপযোগী। তাছাড়া আরো অনেক কারণেই পৃথিবী সূর্যের সবচেয়ে গূরুত্বপূর্ন গ্রহ। সুতরাং, গ অসম্ভব হতে পারে না।

অপশন ঘ) পৃথিবী সূর্যের নিকটতম গ্রহ হতে পারে না। বুধ হলো সূর্যের নিকটতম গ্রহ এবং এটি পৃথিবীর প্রায় ৫৮ মিলিয়ন কিলোমিটার দূরে থাকে। পৃথিবী আমাদের সৌর জগতের তৃতীয় গ্রহ হিসাবে পরিচিত। প্রকৃতির নিয়ম অনুযায়ী, পৃথিবী একটি গ্রহ হিসাবে পর্যায়ক্রমে সূর্যকে ঘিরে ঘুরে চলে যাচ্ছে এবং এর মাঝখানে আরও অন্যান্য গ্রহগুলি অবস্থিত আছে। তাই পৃথিবী সূর্যের নিকটতম গ্রহ হতে পারে না। সুতরাং ঘ অসম্ভব।
৫৮৫.
What is the angle between the hour and minute hand of a clock when it is 3 : 40 pm?
  1. ক
    120°
  2. খ
    110°
  3. গ
    150°
  4. ঘ
    130°
ব্যাখ্যা

Question: What is the angle between the hour and minute hand of a clock when it is 3 : 40 pm?
​
​Solution:
​3 ঘণ্টা 40 মিনিট = 3 + (40/60) ঘণ্টা
= 11/3 ঘণ্টা

​ঘণ্টার কাঁটা 12 ঘণ্টায় 360° ঘুরে
​∴ 1 ঘণ্টায় ঘুরে 360/12 = 30°
​∴​ 11/3 ঘণ্টায় ঘুরে (30 × 11/3) = 110°

​আবার,
​মিনিটের কাঁটা প্রতি মিনিটে 6° করে ঘুরে
​∴ 40 মিনিটে ঘুরে (6 × 40) = 240°

সুতরাং, ঘড়ির কাঁটা দুটির মধ্যবর্তী কোণ​ = |240 - 110| = 130°

৫৮৬.
Find the missing character:
  1. ক
    653
  2. খ
    453
  3. গ
    552
  4. ঘ
    853
ব্যাখ্যা

Question: Find the missing character?

Solution:
Logic:
3 × 4 + 1 = 13

13 × 4 + 1 = 53

53 × 4 + 1 = 213

so, 213 × 4 + 1 = 853

৫৮৭.
Find the missing number-
  1. ক
    17
  2. খ
    13
  3. গ
    14
  4. ঘ
    15
ব্যাখ্যা
Question: Find the missing number-

Solution:
In 1st figure:
31 + 18 = 49 ⇒ √(49) = 7

In 2nd figure:
67 + 14 = 81 ⇒ √(81) = 9

In 3rd figure:
99 + 70 = 169 ⇒ √(169) = 13
৫৮৮.
Your doctor gives you 3 pills to take one for every half hour. How long does it require to take all the pills?
  1. ক
    ক) Half Hours
  2. খ
    খ) One Hour
  3. গ
    গ) One and Half Hours
  4. ঘ
    ঘ) Two Hours
  5. ঙ
    ঙ) None of these
ব্যাখ্যা
Question: Your doctor gives you 3 pills to take one for every half hour. How long does it require to take all the pills?

Solution:
If you're taking 3 pills,
one for every half hour, it means you take a pill every 30 minutes.

So, to calculate the total time required to take all the pills, you multiply the time interval by the number of pills minus one (since you don't need to take a pill after the last interval):

Total time = (Number of pills - 1) × Time interval
= (3 - 1) × 30 minutes
= 2 × 30 minutes
= 60 minutes
= 1 hour

It requires 1 hour to take all the pills.
৫৮৯.
An accurate clock shows 3:00 PM. Through how many degrees will the hour hand rotate when the clock shows 9:00 PM?
  1. ক
    150°
  2. খ
    360°
  3. গ
    180°
  4. ঘ
    90°
ব্যাখ্যা

Question: An accurate clock shows 3:00 PM. Through how many degrees will the hour hand rotate when the clock shows 9:00 PM?

Solution:
From 3.00 pm to 9.00 pm,
total time = 9 - 3 = 6 hours

We know,
Angle traced by hour hand in 12 hours =  360°

∴ Angle traced by hour hand in 6 hours, 
= (360 × 6)/12
= 180°

৫৯০.
In a certain code, PLANE = 26435 and EARTH = 54917, how is PEART coded in the language?
  1. ক
    65392
  2. খ
    95471
  3. গ
    25491
  4. ঘ
    78496
ব্যাখ্যা
Question: In a certain code, PLANE = 26435 and EARTH = 54917, how is PEART coded in the language?

Solution:
Given,
P   L  A   N  E
↓   ↓   ↓   ↓   ↓
2  6   4   3   5

and
E   A  R   T  H
↓   ↓   ↓   ↓   ↓
5   4  9   1   7

So 
P  E   A  R   T
↓   ↓   ↓   ↓   ↓
2   5  4   9   1
৫৯১.
If England is written as 1234526 and France is written as 785291, then Greece is written as_____
  1. ক
    ক) 392291
  2. খ
    খ) 381191
  3. গ
    গ) 382292
  4. ঘ
    ঘ) 392191
ব্যাখ্যা
Question: If England is written as 1234526 and France is written as 785291, then Greece is written as_____

Solution: 
England is written as 1234526
E = 1
n = 2
g = 3
l = 4
a = 5
n = 2
d = 6

France is written as 785291
F = 7
r = 8 
a = 5
n = 2
c = 9
e = 1

So, GREECE will be = 381191
৫৯২.
একটি ঘড়ির মিনিটের কাঁটা ১০ মিনিটে কত ডিগ্রি কোণ অতিক্রম করে?
  1. ক
    ৫৫°
  2. খ
    ৩০°
  3. গ
    ৬৬°
  4. ঘ
    ৬৫°
  5. ঙ
    ৬০°
ব্যাখ্যা

প্রশ্ন: একটি ঘড়ির মিনিটের কাঁটা ১০ মিনিটে কত ডিগ্রি কোণ অতিক্রম করে?

সমাধান:
আমরা জানি,
মিনিটের কাঁটা ৬০ মিনিটে অতিক্রম করে = ৩৬০°
∴ ১০ মিনিটে অতিক্রান্ত কোণ = (৩৬০ × ১০)/৬০
= ৩৬০০/৬০
= ৬০°

৫৯৩.
If p ⊗ q = p - q + (p × q), what is the value of 5 ⊗ 2?
  1. ক
    10
  2. খ
    13
  3. গ
    7
  4. ঘ
    8
ব্যাখ্যা

Question: If p ⊗ q = p - q + (p × q), what is the value of 5 ⊗ 2?

Solution:
দেওয়া আছে, p ⊗ q = p - q + (p × q)

এখন, p = 5 এবং q = 2 বসিয়ে পাই,
⇒ 5 ⊗ 2 = 5 - 2 + (5 × 2)
⇒ 5 ⊗ 2 = 3 + 10
⇒ 5 ⊗ 2 = 13

∴ সুতরাং, নির্ণেয় মান হলো 13।

৫৯৪.
Which of the following pairs of crops will grow together in field 3 if no other crops are planted in the field and no fertilizers or pesticides are applied?
  1. ক
    ক) F and H
  2. খ
    খ) F and I
  3. গ
    গ) G and H
  4. ঘ
    ঘ) G and I
ব্যাখ্যা
Question: Which of the following pairs of crops will grow together in field 3 if no other crops are planted in the field and no fertilizers or pesticides are applied?

Solution: 
ফিল্ড ৩ এ উৎপাদন করা যায় F, G, H, I
F উৎপাদনের জন্য সার x প্রয়োজন। 
H উৎপাদনের জন্য সার y প্রয়োজন। 

অতএব, এক্ষেত্রে G ও I ফিল্ড ৩ এ উৎপাদন করা যায়।  
৫৯৫.
Sunday, Monday, Wednesday, Saturday, Wednesday, Monday, .....
  1. ক
    Sunday, Monday
  2. খ
    Sunday, Sunday
  3. গ
    Sunday, Wednesday
  4. ঘ
    Sunday, Saturday
ব্যাখ্যা
Question: Sunday, Monday, Wednesday, Saturday, Wednesday, Monday, .....

Solution:
Sunday to Monday = no gap
Monday to Wednesday = One day gap.
Wednesday to Saturday = Two days gap.
Saturday to Wednesday = Three days gap.
Wednesday to Monday = Four days gap.
In the next term there must be five days and six days gap.
So, Next term would be Sunday, Sunday.
৫৯৬.
How many days are there in n weeks n days?
  1. ক
    (8n + 1) days
  2. খ
    6n days
  3. গ
    8n days
  4. ঘ
    9n days
ব্যাখ্যা
Question How many days are there in n weeks n days?

Solution:
Number of days in n weeks = 7 × n = 7n days

∴ Number of days in n weeks n days = 7n + n days
= 8n days
৫৯৭.
Students of a class stand in a queue. If Raju is 22nd in order from both ends, how many students are there in the queue?
  1. ক
    42
  2. খ
    44
  3. গ
    43
  4. ঘ
    45
ব্যাখ্যা
Question: Students of a class stand in a queue. If Raju is 22nd in order from both ends, how many students are there in the queue?

Solution:
এক দিক থেকে রাজুর অবস্থান ২২ তম অর্থাৎ সে সহ ২২ জন।
অপর দিক থেকে তার অবস্থান ২২ তম অর্থাৎ সে বাদে আরও ২১ জন আছে।
∴ ঐ সারিতে মোট ছাত্র আছে (২২ + ২১) জন = ৪৩ জন 
৫৯৮.
A boy is sitting on the back seat of a car. When the driver suddenly starts the car, the boy experiences a backward force -
  1. ক
    ক) Always
  2. খ
    খ) Sometimes
  3. গ
    গ) Often
  4. ঘ
    ঘ) Never
ব্যাখ্যা
থেমে থাকা বাস হঠাৎ চলতে শুরু করলে বাস যাত্রীরা সবসময় পিছনের দিকে হেলে পড়েন জড়তার কারণে।

চলন্ত বাস থেকে নামতে গেলে ঠিক তার বিপরীত ব্যাপারটি ঘটে। পুরাে শরীরটি গতিশীল অবস্থায় পা যখন মাটি স্পর্শ করে, শরীরের নিচের অংশ স্থির হয়ে গেলেও উপরের অংশ গতিশীল থেকে যায় এবং যাত্রী সামনে হুমড়ি খেয়ে পড়ে যায়। কোনাে বস্তুর দিক পরিবর্তনের ক্ষেত্রেও আমরা জড়তার প্রভাব অনুভব করি। যদি কোনাে বাস বা গাড়ি হঠাৎ বাক নেয়, যাত্রীরা অন্য পাশে ঝুঁকে পড়ে জড়তার কারণে।
৫৯৯.
Find the odd one out.
  1. ক
    2 : 4 : 12
  2. খ
    9 : 18 : 72
  3. গ
    7 : 14 : 42
  4. ঘ
    5 : 10 : 30
ব্যাখ্যা

Question: Find the odd one out.

Solution: 
Here, 'first number × 2 = second number ; second number × 3 = third number' 

Look at the pattern in each option.
a) 2 : 4 : 12
2 × 2 = 4
4 × 3 = 12

c) 7 : 14 : 42 
7 × 2 = 14
14 × 3 = 42

d) 5 : 10 : 30 
5 × 2 = 10
10 × 3 = 30

But,
b) 9 : 18 : 72
9 × 2 = 18, but 18 × 4 = 72 (not × 3)
Here the multiplier changes to × 4 instead of × 3

Therefore, option b) breaks the consistent pattern of × 2 followed by × 3.

So the odd one out is b) 9 : 18 : 72

৬০০.
A buzzer sounds every 15 minutes. If the buzzer sounded at 12.40, which of the following could be a time at which the buzzer sounded?
  1. ক
    ক) 4.05
  2. খ
    খ) 6.45
  3. গ
    গ) 7.15
  4. ঘ
    ঘ) 8.10
ব্যাখ্যা
Question: A buzzer sounds every 15 minutes. If the buzzer sounded at 12.40, which of the following could be a time at which the buzzer sounded?

Solution: 
A buzzer sounds every 15 minutes.
 the buzzer sounded at 12.40।

4.05 - 12.40 = 265 min ; not divisible by 15
6.45 - 12.40 = 425 min ; not divisible by 15
7.15 - 12.40 = 455 min ; not divisible by 15
8.10 - 12.40 = 510 min ;  divisible by 15
the buzzer could sound at 8.10