### GRE Math Prep Exam Question: Spot the error(s).

07:42 pm
Amy has a bucket which contains 4 2/3 gallons of water. She pours out 1/4 of the water. After several hours pass, 3/7 of the water remaining in the bucket evaporates. How many gallons of water remain?

Here's How to Crack It

Your impulse may be to convert all those fractions into decimals. Don't. First off, they're fairly messy as decimals (3.7 ~ 0.42857 ... ), and secondly, there are some nice simplifications we can do with the fractions.

Start with that 4 2/3 gallons. Convert it into an improper fraction, which means it is 12/3 + 2/3 = 14/3. Now we want to find 1/4 of 14/3, and then 3/7 of that. So we want to find 14/3 x 1/4 x 3/7.

Notice that we can simplify the 3 in the denominator of the first fraction with the 3 in the numerator of the last fraction, leaving us 14/1 x 1/4 x 1/7.

Simplify a 7 from the top of the first fraction and the bottom of the last, leaving 2/1 x 1/4 x 1/1.

Now simplify out a 2 from the first and middle fractions, leaving 1/1 x 1/2 x 1/1. Enter in 1 on the top of the fraction box, and 2 on the bottom.

hani_backup

S M T W T F S
1
234 56 7 8
9101112131415
16171819202122
23242526272829
30

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