Social Distancing with Data Sufficiency Challenge! – Day 9

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This series is designed to help you step up your Data Sufficiency practice while we all spend a little extra time at home during the coronavirus situation; I’m going to publish one practice Data Sufficiency question each day! You can choose to do all of them, or none of them. 

Click on the tag “Social Distancing DS Challenge” at the bottom of this post to see all of the questions in this series! 

And remember to take whatever precautions you need to stay healthy over the next few weeks! 

Question #9

If 4x + 2y = 24, what is the value of x ?

(1) x is a prime number

(2) y = 2x


Even if we know x is a prime number, there are many possible values. Statement (1) is not sufficient. For statement (2), however, we can substitute a value in for y:
4x + 2y = 24
4x + 2(2x) = 24
4x + 4x = 24
8x = 24
x = 3

For the most savvy test-takers, however, all that math isn’t necessary. Merely recognizing that statement (2) provides information to relate one variable in terms of the other– so we can reduce the equation in the setup to a single-variable equation, meaning that we only need a single equation to solve for the single variable– is enough to grab the points and move on. The correct answer is (B).