PSAT Math Multiple-Choice Question 110: Answer and Explanation

Question: 110

Christen wants to buy dishes that cost $17.30 each and bowls that cost $14.90 each. A 15% discount will be applied to the entire purchase and no tax is charged. If Christen buys 3 dishes, which equation relates the number of bowls purchased, n, and the total cost in dollars, x?

• A. 51.90 + 14.90n = 1.15x
• B. 51.90 + 14.90n = 0.85x
• C. 1.15(51.90 + 14.90n) = x
• D. 0.85(51.90 + 14.90n) = x

Correct Answer: D

Explanation:

D

The question asks for an equation that models a specific situation. Translate the question in Bite-Sized Pieces and eliminate after each piece. One piece of information says that a 15% discount will be applied. A 15% discount would be calculated with a multiplier of 0.85 (1–0.15), so eliminate (A) and (C), which multiply by 1.15 (an increase of 15%) instead. Compare the remaining answers. The difference between (B) and (D) is where the 15% discount is being applied. The question states that x is the total cost in dollars. The discount should be applied to the original purchase price of the dishes and bowls, so eliminate (B). The correct answer is (D).