If the average of 1, 2, 4, 5, 6, 9, 9, 10, 12 and x is 7, what is the value of x?
Choose the correct choice from the following:	A) 7	B) 9	C) 11	D) 12	E) 13

Rationale: "sum of the deviations of the numbers in the set from the mean is always zero 1 , 2 , 4 , 5 , 6 , 9 , 9 , 10 , 12 mean is 7 so the list is - 6 - 5 - 3 - 2 - 1 + 2 + 2 + 3 + 5 . . . this shud total to zero but this is - 5 , hence we need a number that is 5 more than the mean to get a + 5 and make it zero hence the answer is 7 + 5 = 12 d"
Answer: D