What is the average of first 21 multiples of 7 ?  Pick one.
A) 22
B) 77
C) 88
D) 21
E) 65
Required average = 7(1+2+....+21) / 21   (7/21)X ( (21x22) / 2 ) (because sum of first 21 natural numbers)   = 77   Answer:77
<result>B</result>
What is the average of first 21 multiples of 7 ?