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Prep question

by hnature0704 » Tue Nov 09, 2010 3:19 am
The number 75 can be written as the sum of the squares of 3 different positive integers. What is the sum of these 3 integer?

a) 17
b) 16
c) 15
d) 14
e) 13

I understand that the prime number of 75 is 5+5+3 = 13 but what does it mean by "the sum of the "squares" of 3 different positive integers? Thank you so much.
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by Rahul@gurome » Tue Nov 09, 2010 3:27 am
Perfect squares less than 75 are 1, 4, 9, 16, 25, 36, 49, and 64.
Now using hit and trial, 75 = 1 + 25 + 49
Sum of the 3 integers = 1 + 5 + 7 = 13

The correct answer is E.
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by beat_gmat_09 » Tue Nov 09, 2010 3:28 am
hnature0704 wrote:The number 75 can be written as the sum of the squares of 3 different positive integers. What is the sum of these 3 integer?

a) 17
b) 16
c) 15
d) 14
e) 13

I understand that the prime number of 75 is 5+5+3 = 13 but what does it mean by "the sum of the "squares" of 3 different positive integers? Thank you so much.
x^2+y^2+z^2 = 75
check for 3 different numbers whose sum of square of numbers i 75.
7,5,1. 7^2 + 5^2+1^2 = 49+25+1 = 75
7+5+1 = 13
Choose E
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