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 Stream of consciousness:
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
Thus, the answer is (B).