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## Official Guide Explanation:Data Sufficiency #155

Background

This is just one of hundreds of free explanations I've created to the quantitative questions in The Official Guide for GMAT Review (12th ed.). Click the links on the question number, difficulty level, and categories to find explanations for other problems.

These are the same explanations that are featured in my "Guides to the Official Guide" PDF booklets. However, because of the limitations of HTML and cross-browser compatibility, some mathematical concepts, such as fractions and roots, do not display as clearly online.

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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