What is the average of first 21 multiples of 8 ? Choices.
A) A)70
B) B)77
C) C)79
D) D)81
E) E)88
Required average = 8(1+2+....+21) / 21   (8/21)X ( (21x22) / 2 ) (because sum of first 21 natural numbers)   = 88   88
<result>E</result>
What is the average of first 21 multiples of 8 ?