Mary buys last year's best-selling novel, in hardcover, for $18.00. This is with a 25% discount from the original price. What was the original price of the novel?

A 25% discount means u paid 75%

75% of the original price is 18 ...

0.75x = 18 ... with x being the original price

x = 18 / 0.75

x = 24 < = = the original price

Discount ⇒ 25%

The price after discount ⇒ 100% - 25% = 75%

Solution:

original price = percentage of original/percentage after discount * price after discount

original price = 100%/75% * 18

original price = 100/75 * 18

original price = 4/3 * 18

original price = 24

The original price was $24.00