Question

What is the average of the squares of the counting numbers from 1 to 7?

• A. 21
• B. 20
• C. 22
• D. 25

Answer 1

Answer:

B. 20

The average of the squares of the counting numbers from 1 to n is given by = (n+1)(2n+1)/6 The average of the squares of the counting numbers from 1 to 7 is = (7 +1)(2×7 + 1)/6 = 8 × 15/6 = 20