ব্যাংক ডেইলি কুইজ [লং কোর্সের অংশ]

Question: A sales representative sells goods worth Tk. 22,000. If his commission rate is 12.5%, what is the amount of commission he earns?

Solution:
Commission = 12.5% of 22000
= (125/10) × (1/100) × 22000
= (125/1000) × 22000
= 2750

Question: (a% of 10b) + (b% of a) is equal to:

Solution:
According to question
(a% of 10b) + (b% of a)
= 10b × (a/100) +  a × (b/100)
= (ab/10) + (ab/100)
= [(10ab + ab)]/100
= 11ab/100
= 11ab%

Or, we can write 11% of ab.

Question: The marked price of a t-shirt was Tk. 800. A man bought the same for Tk. 420 after getting two successive discounts. the first being 25%. then the second discount rate is-

Solution:
Marked price = 800
Actual price = 420
First discount = 25%
Let the second discount be x%

Then, we can write

after 25% discount,
discounted amount = 800 × (25/100)
= 200

New price = 800 - 200
= 600 Tk

Again, second discount,
discounted amount = 600 × (x/100)
= 6x

New price = 600 - 6x

ATQ,
600 - 6x = 420
⇒ 600 - 420 = 6x
⇒ 6x = 180
⇒ x = 30

∴ Second discount = 30%

Question: A number reduced by 25% becomes 225. What percent should it be increased so that it becomes 390?

Solution:
Let
the number be x

Now
x - 25% of x = 225
⇒ x - 25x/100 = 225
⇒ (100x - 25x)/100 = 225
⇒ 75x/100 = 225
⇒ 75x = (225 × 100)
⇒ x =  (225 × 100)/75
∴ x = 300

∴ Required increase 
= (390 - 300)
= 90

∴ Increase percentage :
= (90/300) × 100%
= 30%

Question: If the list price of a mobile phone is Tk. 10000, and a Tk. 1500 discount is offered on the mobile phone, then what is the discount percentage?

Solution:
Marked Price = Tk. 10000
Discount = Tk. 1500

∴ Discount (%) = (Discount/marked Price) × 100%
∴ Discount (%) = (1500/10000) × 100%
= 15%

∴ So the discount percentage is 15%.

Question: The price of the sugar rise by 25%. If a family wants to keep their expenses on sugar the same as earlier, the family will have to decrease its consumption of sugar by-

Solution:
২৫% বৃদ্ধিতে দাম = (১০০ + ২৫) = ১২৫টাকা।
 
১২৫ টাকায় চিনি খাওয়া কমে = ১২৫ - ১০০ = ২৫ টাকা
∴ ১ টাকায় চিনি খাওয়া কমে = ২৫/১২৫ টাকা
∴ ১০০ টাকায় চিনি খাওয়া কমে = (২৫ × ১০০)/১২৫
= ২০ টাকা
 
অর্থাৎ, শতকরা ২০% কমিয়েছিল

Question: A trader marks his goods at 40% above the cost price but allows a discount of 20% on the marked price. His profit percentage is-
 
Solution: 
Let
the Cost Price of the goods Tk.100

∴ Marked price of the goods  = 100 + 40% of 100
= 100 + (40 × 100)/100
= 100 + 40 
 = 140

∴ Selling Price of the goods = 80% of 140
= (140 × 80)/100
= 112

∴ profit = 112 - 100 = 12 Tk.

∴ profit percentage is = (12/100) × 100%
= 12%

Question: In a test, minimum passing percentage for girls and boys are 45% and 60% respectively. A boy scored 767 marks and failed by 313 marks. What are the minimum passing marks for girls?

Solution:
Minimum pass percentage for Boys = 60%
Minimum pass percentage for girls = 45%

A boy gets 767 and failed by 313
∴ Passing marks for boys= 767 + 313 = 1080
 
Now
60% = 1080
⇒ 1% = 1080/60
⇒ 45% = (1080 × 45)/60
= 810

Question: Find the difference of amount if 40% discount is given on Tk. 1000 and two consecutive discounts 30% and 10% are given on the same amount.

Solution:
40% discount on 1000 = 1000 × 40% = 400
 
Two consecutive discounts on 1000.
30% discount on 1000 = 30% of 1000
= 300

After 30% discount on 1000 = 1000 - 300
= 700

Again,
After 10% discount on 700 = 10% of 700
= 70

Total discount = 300 + 70
= Tk. 370
So, the difference = 400 - 370
= Tk. 30

Question: A student scores 55% marks in 8 papers, each carrying 100 marks. He obtains 15% of his total obtained marks in the Bangla paper. How many marks did he score in Bangla?

Solution:
৮ টি বিষয়ে মোট নম্বর = 8 × 100 = 800
সে নম্বর পেয়েছে = 800 এর 55%
= 800 এর 55/100
= 440

∴ সে বাংলায় নম্বর পেয়েছে = 440 এর 15%
= 440 এর 15/100
= 66

Question: A student mistakenly multiplied a number by 7/10 instead of 7/5. Find the percentage error in the result.
 
Solution:
Let
The number is 100.

ATQ,
The actual calculation be: (7/5) × 100 = 140
and error calculation be: (7/10) × 100 = 70

∴ Difference = 140 - 70 = 70

∴ Percentage error = (70/140) × 100 = 50%

Question: 50% of a number is 1200. What is 6% of that number?

Solution:
Let the number be x

Then,
50% of x = 1200
⇒ 50x/100 = 1200
⇒ x = (1200 × 100)/50
⇒ x = 2400

∴ 6% of 2400
= 2400 × (6/100)
= 144 

Question: Arif bought a ticket of a cinema for Tk. 25 and later sold the ticket to Rafi for Tk. 75. What was the percent increase in the price of the ticket?

Solution:
ক্রয়মূল্য = 25 টাকা
বিক্রয়মূল্য = 75 টাকা
∴ লাভ = 75 - 25 = 50 টাকা

25 টাকায় লাভ হয় = 50 টাকা
1 টাকায় লাভ হয় = 50 / 25 টাকা
∴ 100 টাকায় লাভ হয় = (50 × 100)/25 টাকা = 200 টাকা

∴ শতকরা লাভ 200%

Question: If 75% of the students in a school are boys and the number of girls is 520, the number of boys is:

Solution:
Percentage of boys = 75%
Percentage of girls = 25%

ATQ,
∴ Number of  Girls = 25% = 520
⇒ 25% = 520
⇒ 1% = 520/25
∴ 75% = (520 × 75)/25
= 1560

Question: In an election, 4% of the total votes cast are invalid. Of the valid votes, one candidate secures 55% and wins the election by a margin of 4,800 votes. Find the total number of votes cast.

Solution:
বিজয়ী প্রার্থী ভোট পায়= 55%
বৈধ ভোট = (100 - 4)% = 96%

বিজয়ী প্রার্থী বৈধ ভোটের শতকরা পায় = (55 × 96)/100
= 52.8%

পরাজিত প্রার্থী ভোট পায় = (96 - 52.8)%
= 43.2%

বিজয়ী প্রার্থী ও পরাজিত প্রার্থীর ভোটের পার্থক্য = (52.8 - 43.2)%
= 9.6%

প্রশ্নমতে
 9.6% = 4800
 1% = 4800/9.6
 100% = (4800 × 100)/9.6
= 50000