q 108) from 198 700 level questions

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q 108) from 198 700 level questions

by MG368 » Tue Nov 24, 2009 10:38 pm
I got stuck in this one...

108) 75 can be written as the sum of the squares of 3 different positive integers. What is sum of these integers?
a. 17
b. 16
c. 15
d. 14
e. 13

does anyone know the explanation.. the answer is (e) as per the solution but can't get how or why?

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by nikilnikil » Tue Nov 24, 2009 11:32 pm
this has to be calculated using brute force

the squares which are below 75 are

1 4 9 16 25 36 49 64

lets take largest number first
64 , remaining 75-64 = 11 cannot be expressed as sum of 2 squares.

49, reamining 75-49 = 26 = 1 + 5*5 . This is the solution.

so, 1,5,7 are the three numbers

1+5+7 = 13

~Nik

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by RoadtoIVY » Wed Nov 25, 2009 1:09 am
Hey MG638, could you please share those 198 questions?

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by MG368 » Wed Nov 25, 2009 7:48 am
https://www.beatthegmat.com/198-level-70 ... 43783.html

check out this link.. you can download the questions and solutions!

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by RoadtoIVY » Wed Nov 25, 2009 11:14 am
Thanks so much!! Happy GMATing....

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by regor60 » Mon Nov 30, 2009 8:01 am
A tip is that you know that the average squared number is 25 so that the average number is 5...gives you a starting point and it quickly becomes obvious