Fraction and Simplification, Average and Mean

The average of six numbers is 30. If the average of first four is 25 and that of last three is 35, the fourth number is:

The average of 6 numbers is 7. The average of three numbers of them is 5. What will be the average of the remaining numbers?

In a school, students may bring breakfast, buy it, or may not eat breakfast. If 1/4 of the students bring breakfast, 1/7 don't eat breakfast, and 187 buy it, how many students bring breakfast?

The average of 6 numbers in 25. If 3 more numbers, with an average of 22 are added to these numbers, what will be the average of the combined 9 numbers?

The average of 8 numbers is 8. If 4 is subtracted from each of 6 of the numbers, what is the new average?

In a set of 3 numbers, the average of first two numbers is 2, the average of the last two numbers is 3, and the average of the first and the last numbers is 4. What is the average of three numbers?

The average age of the 20 aspirants of a class is 19.2 years. After some time two more aspirants join them and then average is increased by 0.3 years. Find the difference between the age of new aspirants.

If the mean of numbers 28, x, 42, 78 and 104 is 62, what is the mean of 48, 62, 98, 124 and x?

If the sum of A and B is 40, and if C = 32, what is average value of A, B and C?

Three math classes, X, Y, and Z, take an algebra test. The average score in class X is 83. The average score in class Y is 76. The average score in class Z is 85. The average score of all students in classes X and Y together is 79. The average score of all student classes Y and Z together is 81. What is the average for all the three classes?

Hamed's average on 4 tests is 80. Assuming he can earn no more than 100 on any test, what is the least he can earn on his 5^th test and still have a chance for an 85 average after seven tests?

If the average (arithmetic mean) of x and y is 60 and the average (arithmetic mean) of y and z is 80, what is the value of (z-x)?

Q (33-56): Read the following questions carefully and choose the right answer.
৩৩) Which one of the following numbers can be removed from the set S = (0, 2, 4, 5, 9) without changing the average of set S?

The average of 6 numbers is 25. If 3 more numbers, with an average of 22 are added to these numbers, what will be the average of the combined 9 numbers?

The average age of a group of 15 employees is 24 years. If 5 more employees join the group, the average age increases by 2 years. Find the average age of the new employees.

'Ambidexter' means-

The average of a, b, c is 6 and a - b = 4, ab = 21, what is the value of c? 

If 6 and x have the same mean as 2, 4 and 24, what is the value of x?

The average of a set of 12 numbers, which includes 34 is A. If 34 is removed from the set and 38 is included to the set. What is the average of new set of numbers in terms of A?

A player's average test score on 4^th test is 78. What must be his score on a 5^th test for average score on the 5^th tests to be 80?