Official Guide Explanation:
Data Sufficiency #155




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.

Click here for an example of the PDF booklets. Click here to purchase a PDF copy.


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.

Click here for the full list of GMAT OG12 explanations.


You should follow me on Twitter. While you're at it, take a moment to subscribe to GMAT Hacks via RSS or Email.

Total GMAT Math

The comprehensive guide to the GMAT Quant section. It's "far and away the best study material available," including over 300 realistic practice questions and more than 500 exercises!
Click to read more.