PSAT Math Multiple-Choice Question 624: Answer and Explanation

Question: 624

What is the value of x in this pair of equations?

• A. -20
• B.
• C.
• D.

Correct Answer: B

Explanation:

(B) First, let's distribute the 4 in the second equation:

Next, notice that if you multiplied the first equation by 8, the y-terms (and in fact the entire left-hand side of both equations) would be the same:

You could subtract the second equation from the first to cancel the y-terms:

Add 5 to both sides:

5 = 6x

Now divide by 6 to solve for x:

This is choice (B).