Question

There are 80 questions on a college entrance examination. Two points are awarded for each correct answer, and one-half point is deducted for each incorrect answer. How many questions does Tami need to answer correctly in order to score at least 100 on the test? Assume that Tami answers every question.

Answer 1

If she gets x right, then she gets 80-x wrong. That means we need

2x - 1/2 (80-x) >= 100
5/2 x - 40 >= 100
5/2 x >= 140
x >= 56

Answer 2

2+2

Answer 3

Hey Steve, where did the 5/2 come from?

Answer 4

2x+1x/2

Common denominator
4x/2+1x/2