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
Faster way to solve this?
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- jayhawk2001
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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.
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.