Set S consists of integers {4, 7, 10, 14, 15}. If integer n is included in the set, the average (arithmetic mean) of set S will increase by 50%. What is the value of integer n?  Select
A) 28	B) 32	C) 36	D) 40	E) 44

Rationale: "the average of the numbers in set s is 10 . if we increase the mean by 50 % , the new mean is 15 . thus , on average , 5 numbers increase by 5 . therefore n = 15 + 25 = 40 the answer is d ."
Answer: D