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## Official Guide Explanation:Data Sufficiency #18

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: 18
Page: 274
Difficulty: 4 (Moderately Easy)
Category 1: Geometry > Rectangular Solids and Cylinders > Rectangular Solids
Category 2: Geometry > Quadrilaterals >
Category 3: Word Problems > Geometry Problems >

Explanation: We're given the dimensions of rectangular blocks and we want to determine how many such blocks would fit inside a rectangular box. At the very least, we'll need to know the size of the box before we can answer the question.

Statement (1) is insufficient. Essentially, this tells us about only two of the three dimensions, and we don't know which of the two dimensions it's addressing. Another way of looking at it is that, while we know how many blocks make up the bottom layer, we don't know how many layers there are. Without knowing the size of the box, we can't figure that out.

Statement (2) is sufficient. Given the size of the box, we can determine how many blocks would fit inside it. It would take some time to work through all of the possibilities are come up with a numerical answer, but since this is a DS question, we can rest assured that we would eventually find an answer and select choice (B).

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