PSAT Math Multiple-Choice Question 782: Answer and Explanation

Question: 782

If the sale price on a coat is $72 and the original price of the coat was $90, what is the percent discount from this sale?

• A. 14%
• B. 20%
• C. 26%
• D. 80%

Correct Answer: B

Explanation:

(B) This question is asking you what percent the discount is of 90. First, you need to know what the discount is, which you can get by subtracting the new price from the original price: 90 - 72 = 18. Then, you can figure out what percentage 18 is of 90 by setting up a proportion, recognizing that 90 represents 100% of the quantity:

Next, cross multiply:
90x = 1800
Dividing by 90 yields x = 20. So $18 is 20% of $90, which is choice (B).
As an alternative to this approach, you could plug the values from the problem into this formula for a percentage change:
% Change = 100 ×