Official Guide Explanation:
Data Sufficiency #155

Background

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Solution and Metadata

Question: 155
Page: 287
Difficulty: 5 (Moderate)
Category 1: Arithmetic > Ratio and Proportion >
Category 2: Word Problems > Other >

Explanation: The question is a wordy one, but it basically gives you a ratio of the 1970 mixer price to the 1989 mixer price, and asks what the 1970 mixer price is. Statement (1) gives you a difference. Say the 1970 price is x and the 1989 price is y: y - x = 102.40. The question specifies that ((y)/(x)) = 3.56, so you have two linear equations and two variables: you can solve for x, the 1970 mixer price.

Statement (2) is more direct: given the 1989 price and the ratio between the 1970 and 1989 prices, you can solve for the 1970 mixer price. Choice (D) is correct.

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