John found that the average of 15 no.'s is 40. If 10 is added to each number then the mean of number is?	Choose the correct option
A) 50  B) 55  C) 65  D) 72  E) 78

Rationale: ( x + x 1 + . . . x 14 ) / 15 = 40 50 option a
Answer: A