Official Guide Explanation:
Data Sufficiency #88

Background

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Solution and Metadata

Question: 88
Page: 280
Difficulty: 5 (Moderate)
Category 1: Algebra > Linear Equations-Two Unk >
Category 2: Arithmetic > Percents > other

Explanation: The question gives us a formula:

m + r + h = 12,000

We're looking for the value of r.

Statement (1) is insufficient. It does give us another equation:

r + h = (1/3)m

With that, we can substitute (1/3)m for r + h in the original equation. We can then solve for m, but that doesn't help us isolate r.

Statement (2) is sufficient. It gives us an equation as well:

r = 0.2(m + h)

Or:

5r = m + h

We can substitute 5r for m + h in the original equation:

r + 5r = 12,000

6r = 12,000

r = 2,000

Choice (B) is correct.

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