Official Guide Explanation:
Problem Solving #112




This is just one of hundreds of free explanations I've created to the quantitative questions in The Official Guide for GMAT Quantitative Review (2nd 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: 112
Page: 76
Difficulty: 6 (Moderately Difficult)
Category 1: Word Problems > Other >
Category 2: Arithmetic > Properties of Integers > Factors and Multiples

Explanation: Whenever you see a phrase like "none left out," the question is probably about factors and multiples. The factors of 21 are 1, 3, 7, and 21, so if no white tulips are to be left out, there must be 1, 3, 7, or 21 bouquets. Similarly, since the factors of 91 are 1, 7, 13, and 91, there must be 1, 7, 13, or 91 bouquets if no red tulips are to be left out. Since both must be considered, the only possible numbers of bouquets are 1 or 7. We're looking for the greatest possible number, so 7 is the answer. Choice (E) is correct.

Click here for the full list of GMAT Quant Review explanations.


You should follow me on Twitter. While you're at it, take a moment to subscribe to GMAT Hacks via RSS or Email.

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.