PSAT Math Multiple-Choice Question 332: Answer and Explanation

Question: 332

Clarice had twice as many nickels as dimes in her piggy bank. When she adds 4 more nickels, she has three times as many nickels as dimes. What was the total number of nickels and dimes in Clarice's piggy bank before she added the additional nickels?

• A. 4
• B. 8
• C. 12
• D. 16

Correct Answer: C

Explanation:

C

Difficulty: Easy

Getting to the Answer: Translate the words in the question into equations. Let n be the original number of nickels and d be the number of dimes. That there were "twice as many nickels as dimes" means that n = 2d. When 4 nickels are added, the number of nickels is 3 times the number of dimes. Thus, n + 4 = 3d. Substitute 2d for n in the second equation: 2d + 4 = 3d. Subtract 2d from each side to get 4 = d. The question asks for the original number of coins. The original number of nickels is n = 2d = 8 and the total number of coins is 4 + 8 = 12, which is (C).