Bunuel wrote:

A student has an average (arithmetic mean) score of 72 on his first 3 tests. Which of the following is the least average score needed on his next two tests to bring his overall average to at least an 80?

A. 89

B. 90

C. 91

D. 92

E. 104

Try Plug In answer choices

Start with centre (C) = 91

Total score = (72 x 3 + 91 x 2)/5 = 398/5 = 79.6 < 80 Eliminate

Now, we know that we need a slightly greater number than 91

Try (D) = 92

Total score = (72 x 3 + 92 x 2)/5 = 400/5 = 80 = 80

Answer (D) = 92

_________________

"Do not watch clock; Do what it does. KEEP GOING."