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## Official Guide Explanation:Data Sufficiency #21

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: 21
Page: 274
Difficulty: 5 (Moderate)
Category 1: Arithmetic > Percents > other
Category 2: Arithmetic > Sets > 2 sets
Category 3: Word Problems > Sets >

Explanation: We're looking for the percentage of drama club members who are female.

Statement (1) is insufficient. 40 percent of the female students are members of the drama club, but those 40 percent could represent all of the drama club members (e.g., there are no men in drama club), or a much smaller percentage (if there are many men in drama club).

Statement (2) is also insufficient. 25 percent of men are members of the drama club, but by the same reasoning as the previous statement, we don't know what percentage of drama club members those 25 percent of men occupy.

Taken together, the statements are still insufficient. If we knew there were exactly 100 men and 100 women at the school (for instance--any equal number will do), we could determine how many men and women (25 and 40) are in drama club and answer the question. However, we don't know that the number of men and women are equal. If there 200 men and 100 women, the number in drama club is 50 and 40, changing the percentages drastically. Choice (E) is correct.

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