Official Guide Explanation:
Problem Solving #31




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Solution and Metadata

Question: 31
Page: 156
Difficulty: 5 (Moderate)
Category 1: Word Problems > Rate Problems > Speed
Category 2: Algebra > Equations >

Explanation: This is a very popular type of GMAT question, and a tricky one. It's asking for time, and you can manipulate the traditional rate formula to give you time = ((dist)/(rate)). When working with words per minute, "distance" is a misnomer; it's really more like "amount of work" or, in this case, number of words. The question tells us that his number of words is y and his rate is x words per minute, so time = ((dist)/(rate)) = ((y)/(x)), choice (B). This method may seem more abstract (and perhaps for that reason uncomfortable) compared to plugging in values for the variables, but once you've mastered it, it is considerably faster than your other options.

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