PSAT Math Multiple-Choice Question 338: Answer and Explanation

Question: 338

If 6a + 6b = 30 and 3a + 2b = 14, then what are the values of a and b ?

• A. a = 2; b = 2
• B. a = 4; b = 1
• C. a = 1; b = 4
• D. a = 3; b = 1

Correct Answer: B

Explanation:

B

Difficulty: Easy

Getting to the Answer: Looking at the coefficients of the two equations, you'll notice that multiplying the second equation by -3 will allow you to eliminate the b terms:

Solving the resulting equation gives a = 4. Choice (B) is the only choice that contains this value for a, so it must be correct.