PSAT Math Multiple-Choice Question 319: Answer and Explanation

Question: 319

Which value of x makes the equation true?

• A. 7
• B. 9
• C. 17
• D. 19

Correct Answer: D

Explanation:

D

Difficulty: Easy

Category: Solving Equations

Getting to the Answer: Distributing the will result in messy calculations, so clear the fraction instead. Multiply both sides of the equation by the reciprocal of , which is , and isolate x:

Choice (D) is correct.

Alternatively, you could backsolve. Say you started with (B). The left side of the equation would become , which is smaller than 12, so you would move to (C) next. Plugging in 17 gives . This is still smaller than 12 since 12(3) = 36, so the correct answer again must be (D).