On his first 3 tests, Rajeev received an average score of N points. If on his fourth test, he exceeds his previous average score by 20 points, what is his average score for his first 4 tests?
Choose the correct answer
A) N  B) N + 4  C) N + 5  D) N + 10  E) N + 20
Total points from first three tests: 3N   Points on fourth test: N + 20   Total points on all four tests: 3N + (N + 20) = 4N + 20   Average score for first four tests: (4N + 20)/4 = N + 5   Answer is N + 5.
<result>C</result>
On his first 3 tests, Rajeev received an average score of N points. If on his fourth test, he exceeds his previous average score by 20 points, what is his average score for his first 4 tests?