What is the average of first 21 multiples of 7 ?	Choose the correct answer:
A) 55 B) 66 C) 77 D) 88 E) 99
Explanation:   Required average = 7(1+2+….+21) / 21   (7/21)X ( (21×22) / 2 ) (because sum of first 21 natural numbers)   = 77   Answer: 77
<result>C</result>
What is the average of first 21 multiples of 7 ?