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## Official Guide Explanation:Data Sufficiency #129

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: 129
Page: 284
Difficulty: 5 (Moderate)
Category 1: Arithmetic > Descriptive Statistics > other
Category 2: Arithmetic > Percents > other

Explanation: Statement (1) is insufficient. If 25 percent of the projects have 4 or more people, then 75 percent of the projects have 3 or fewer people. The median is somewhere in that 75 percent (it's between the 49th and 51st percent, to be exact), but we don't know whether that's 1, 2, or 3 people.

Statement (2) is also insufficient. By the same reasoning, if 35 percent have 2 or fewer employees, 65 percent have 3 or more. The median is somewhere between 3 and a very large number, but we don't know where.

Taken together, the statements are sufficient. The statements leave us with a middle 40 percent of projects that have both 3 or fewer people and 3 or more people assigned to them. Put it all together, and all of those middle 40 percent of projects have exactly 3 people assigned to them. Since we're talking about the middle 40 percent, the median must be 3. Choice (C) is correct.

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