PSAT Math Multiple-Choice Question 371: Answer and Explanation

Question: 371

Last year, a sand and gravel company sold 280 tons of gravel and 220 tons of sand. This year, the company sold 20 percent more gravel by weight and 25 percent more sand by weight than it sold last year. By approximately what percent did the total weight of sand and gravel sold increase this year over last year?

• A. 22%
• B. 45%
• C. 56%
• D. 111%

Correct Answer: A

Explanation:

A

Difficulty: Medium

Getting to the Answer: To find the total percent increase in weight of sand and gravel sold, first find the total actual change in weight. The total weight sold this year for gravel is 280 + (0.20 × 280) = 336. The total weight sold for sand is 220 + (0.25 × 220) = 275. Therefore, this year's total weight is 336 + 275 = 611. Last year's total weight was 280 + 220 = 500. Thus, the change from last year to this year is 611 - 500 = 111. Now, apply the percent change formula:

Choice (A) is correct.