Question

Mark had 14 problems wrong on his test. his score was 72% correct. how many problems were on the test?

Answer 1

Let x = number of problems on test
If he got 14 wrong, then x - 14 is the number correct.
$\frac{x-14}{x} = .72$
x - 14 = .72x
.28x - 14 = 0
.28x = 14
x = 50

The test consisted of 50 problems.