Target Test Prep 20% Off Flash Sale is on! Code: FLASH20

Redeem
Target Test Prep
5-Day Free Trial
5-day free, full-access trial TTP

Available with Beat the GMAT members only code

MORE DETAILS
Target Test Prep
Magoosh
Magoosh
Study with Magoosh GMAT prep

Available with Beat the GMAT members only code

MORE DETAILS
Magoosh

sum of squares of 3 different positive integers

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Newbie | Next Rank: 10 Posts
Posts: 3
Joined: Mon Dec 19, 2011 5:40 pm
Thanked: 1 times

sum of squares of 3 different positive integers

by smitathakur64 » Tue Dec 27, 2011 7:54 pm
Question: The number 75 can be written as the sum of the squares of 3 different positive integers. What is the sum of these 3 integers?
1)17
2)16
3)15
4)14
5)13

I tried to solve it by trial and error method. Tried all the combinations of squares, till I got to the right answer(1,5,7). Is this the right way of doing it or is there any better and quicker way.
The answer is 13.

Thanks
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3835
Joined: Fri Apr 02, 2010 10:00 pm
Location: Milpitas, CA
Thanked: 1854 times
Followed by:523 members
GMAT Score:770

by Anurag@Gurome » Tue Dec 27, 2011 8:27 pm
smitathakur64 wrote:Question: The number 75 can be written as the sum of the squares of 3 different positive integers. What is the sum of these 3 integers?
1)17
2)16
3)15
4)14
5)13

I tried to solve it by trial and error method. Tried all the combinations of squares, till I got to the right answer(1,5,7). Is this the right way of doing it or is there any better and quicker way.
The answer is 13.

Thanks
Trial and error is the fastest way to answer this question.
The perfect squares under 75 are: 1, 4, 9, 16, 25, 36, 49, and 64
Now we have to find 3 different numbers from the above integers, which add to 75, 1 + 25 + 49 = 75
So, their roots are 1, 5, and 7, which add to 13.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
Top
Post new topic Post Reply
• Page 1 of 1