Average age of 9 members of a club is 29 years. If 2 more persons with the average age of 40 years have become the members of the club, find average age of all the 11 members.
Options:
(A) 15
(B) 31
(C) 77
(D) 99
(E) 22

Average age of 9 members = 29 years; Excess age of 2 new members = (40 - 29) 2 = 22 years
Therefore, Increase in the average age on inclusion of 2 new members = 22112211 = 2 years
Therefore, Average age of 11 members = 29 + 2 = 31 years So the answer is: (B).

Three 6 faced dice are thrown together. The probability that exactly two dice show the same number on them is ?
Options:
(A) 5/16
(B) 5/12
(C) 5/87
(D) 5/56
(E) 5/38

Using question number 11 and 12, we get the probability as
1 - (1/36 + 5/9) = 5/12 So the answer is: (B).

What is the greatest positive integer x such that 2^x is a factor of 8^10?
Options:
(A) 5
(B) 9
(C) 10
(D) 20
(E) 30

8^10 = (2^3)^10 = 2^30 So the answer is: (E).

Which one of the following is not a prime number?
Options:
(A) 31
(B) 61
(C) 71
(D) 73
(E) 91
91 is divisible by 7. So, it is not a prime number. So the answer is: (D).