Question

A student on her first 3 tests received an average score of N points. If she exceeds her previous average score by 20 points on her fourth test, then what is the average score for the first 4 tests?
1. N + 20
2. N + 10
3. N + 4
4. N + 5

Answer 1

Correct Answer - Option 4 : N + 5

Given:

Average score of three students = N points

In fourth test her average exceeds 20 points

Formula used:

Average = Sum of observations/Number of observations

Calculation:

Score in first test = N

Score in three tests = N + N + N = 3N

Score in fourth test = N + 20

Total score for 4 tests = 3N + N + 20

⇒ 4N + 20

Average score for the first 4 tests = 4N + 20/4

⇒ 4(N + 5)/4

⇒ N + 5

∴ The average score for the first 4 tests is N + 5