Official Guide Explanation:
Data Sufficiency #48

Background

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Solution and Metadata

Question: 48
Page: 277
Difficulty: 4 (Moderately Easy)
Category 1: Arithmetic > Ratio and Proportion >
Category 2: Arithmetic > Percents > other

Explanation: Statement (1) is insufficient. The question starts by asking the relationship between two variables--June transactions made by each of two salespeople. This statement adds a third: May transactions by Y. If we call June transactions by X x_j and May transactions by Y y_m, we can set up an equation:

x_j = 1.5y_m

Statement (2) is also insufficient. It says nothing about X. It does give us another relationship:

y_j = 1.25y_m

Taken together, the statements are sufficient. We're looking for ((x_j)/(y_j)), and each of the statements gives us one of those in terms of Y's May transactions. We can plug in each of those equations:

((x_j)/(y_j)) = ((1.5y_m)/(1.25y_m)) = ((1.5)/(1.25)) = (6/5)

Choice (C) is correct.

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