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Faster way to solve this?

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Faster way to solve this?

by kajcha » Sat Sep 01, 2007 1:16 pm
Is there an faster method to solve such problems? I got the answer correct but it was time consuming as I was evaluating numbers

Q. The number 75 can be written as the sum of the squares of 3 different postive integers. What is the sum of these 3 integers?

1) 17

2) 16

3) 15

4) 14

5) 13
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by jayhawk2001 » Sun Sep 02, 2007 4:08 pm
I'd say write down the list of squares i.e.

1 4 9 16 25 36 49 64

The sum has to be 75. So, try plugging numbers in reverse order
(64, 49, etc.) and get the sum to 75

64 + 11 = 75, can't get 11 as sum using any combination above.
So, ignore.

49 + 25 + 1 = 75, yes. there you have it

You don't have to try numbers less than 36 as you can't get a sum
of 75.

Since GMAT problems will have a unique answer, you can stop at
step 2 above.
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by kajcha » Sun Sep 02, 2007 6:22 pm
Thanks jayhawk.. I used similar method...
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