Official Guide Explanation:
Data Sufficiency #D47

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.

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

Solution and Metadata

Question: D47
Page: 25
Difficulty: 5 (Moderate)
Category 1: Arithmetic > Sets > 2 sets
Category 2: Word Problems > Sets >

Explanation: This is an overlapping sets question. We're given the total, and we're given the amounts represented by the two sets, but we don't know how many books are in both sets, or how many are in neither set. We can use the following formula:

80 = 24 + 23 - both + neither

Statement (1) is sufficient. There are 24 fiction books. If 6 more of those were not written in Spanish than written in Spanish, 15 were not written in Spanish and 9 were written in Spanish. That answers the question.

Statement (2) is also sufficient. Of the 23 Spanish books, if 5 more are nonfiction than fiction, 14 are nonfiction and 9 are fiction. Choice (D) is correct.

Click here for the full list of GMAT OG12 explanations.

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.