Averages Q39

39. Find the average of first 20 multiples of 7.

A.70                             B.73

C.73.5                         D.72.5

 Answer:

 Required average = 7(1+2+3 ... + 20) / 20 = [7 * 20 * 21 / 20 * 2] = [147 / 2] = 73.5.