Question

$72 is what percent of $80?

Answer 1

72 = x% of 80
72 = x × 80
72/80 = x
.90 = x

multiply by 100 to convert to percent...

.90 = 90%

Answer 2

80 / 10 = 8 (10 percent of 80)

8 x 9 = 72 (90 percent of 80)

Answer 90%

(The method I showed doesn't apply to all of these type of questions, It's simply to confirm).