Official Guide Explanation:
Data Sufficiency #29

 

 

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.

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Solution and Metadata

Question: 29
Page: 275
Difficulty: 5 (Moderate)
Category 1: Geometry > Rectangular Solids and Cylinders > Cylinders
Category 2: Geometry > Rectangular Solids and Cylinders > Surface Area

Explanation: To find the surface area of a cylindrical surface, you need the circumference of the cylinder (to get that, you need radius or diameter) and the height of the surface. Statement (1) offers the height, but nothing about the circumference. Statement (2) is completely irrelevant, giving you nothing about the height of the shaded band or the circumference.

Taken together, they are still insufficient. (1) isn't enough, and (2) contributes nothing. The correct choice is (E).

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