SAT Math Multiple Choice Practice Question 62: Answer and Explanation

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Question: 62

18. If vw = x, wx = y, and xy = z, which of the following would be equal to yz?

A. v2w2
B. v3w5
C. v4w4
D. v4w6
E. v5w8

Correct Answer: B

Explanation:

B. The answer choices have only v and w in them, so you need to start this problem by turning everything into those letters. You already know that x = vw, so y = wx = w(vw) = vw2. To continue, you need to remember two things: First, the ws both have an "invisible 1" as their exponents, and second, you need to add exponents when you multiply powers of the same bases. Because z = xy, z = (vw)(vw2) = v2w3. You're looking for yz, which your work tells you equals (vw2)(v2w3) = v3w5.

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