Articles published in April 2013

This Problem is Work!

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gmat pumpRaise your hand if you love rate and work questions. They’re awesome, right? They tend to be fairly long, and the set-up is pretty complex, plus we get to build a table before we dive into the equations!

Oh, wait no those are all reasons why we can’t stand these problems.

Give yourself approximately 2 minutes to try the below GMATPrep problem. When you’re done, take a look at it again and ask yourself, Is there a better way to do this thing?

* Pumps A, B, and C operate at their respective constant rates. Pumps A and B, operating simultaneously, can fill a certain tank in 6/5 hours; pumps A and C, operating simultaneously, can fill the tank in 3/2 hours; and pumps B and C, operating simultaneously, can fill the tank in 2 hours. How many hours does it take pumps A, B, and C, operating simultaneously, to fill the tank?

(A) 1/3

(B) 1/2

(C) 2/3

(D) 5/6

(E) 1

Have you got an answer? Pick one anyway. Pretend it’s the real test: you can’t keep going till you pick an answer.

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Challenge Problem Showdown- April 1, 2013

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challenge problem
We invite you to test your GMAT knowledge for a chance to win! Each week, we will post a new Challenge Problem for you to attempt. If you submit the correct answer, you will be entered into that week’s drawing for a free Manhattan GMAT Prep item. Tell your friends to get out their scrap paper and start solving!
Here is this week’s problem:

The ratio of a to b is twice the ratio of b to c.  If ab, and c are positive integers, which of the following statements cannot be true?

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