Question

Find the average of squares of first 5 prime natural numbers.
1. 40
2. 50
3. 52.5
4. 41.6

Answer 1

Correct Answer - Option 4 : 41.6

Given:

First 5 prime natural numbers.

Concepts used:

Prime natural numbers are those which have only 2 factors - 1 and the number itself.

Average = (Sum of all observations)/(Number of observations)

Calculation:

First 5 prime natural numbers are  -

2, 3, 5, 7 and 11

Sum of squares of first 5 prime natural numbers = 2² + 3² + 5² + 7² + 11² 

⇒ 4 + 9 + 25 + 49 + 121 = 208

Average = Sum of all observations/Number of observations

⇒ 208/5 = 41.6

∴ The average of squares of the first 5 prime natural numbers is 41.6.