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Senior Manager
Joined: 08 Aug 2005
Posts: 251

10x/x+y) + (20y/x+y) = k, where x, y and k are integers. If
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26 Apr 2006, 02:40
(10x/x+y) + (20y/x+y) = k, where x, y and k are integers. If x<y. k=?
10
12
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18
20 == Message from the GMAT Club Team == THERE IS LIKELY A BETTER DISCUSSION OF THIS EXACT QUESTION. This discussion does not meet community quality standards. It has been retired. If you would like to discuss this question please repost it in the respective forum. Thank you! To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative  Verbal Please note  we may remove posts that do not follow our posting guidelines. Thank you.



Intern
Joined: 02 Mar 2006
Posts: 21

(10x/x+y) + (20y/x+y) = k
=> (10x + 20y/x+y) = k
=> 10(x + 2y/x+y) = k
as it is given x, y & k are integers we should select x & y such that it divides 10,
factors of 10 are 2 and 5
so we can take x=1 & y=1 or x=1 or y=4
as it is given x<y
x=1 and y=4
by substituting these values we get k=18



GMAT Club Legend
Joined: 07 Jul 2004
Posts: 4836
Location: Singapore

(10x+20y)/(x+y) = k
10(x+2y)/(x+y) = k
Since K is an integer, x+y must be a 10 to cancel out the 10 in the numerator.
x+y = 10 and we have x<y, so possible sets:
x,y
1,9 > K = 19
2,8 > K = 18
3,7 > K = 17
4,6 > K = 16
Only 18 is in the list of answers given.



VP
Joined: 06 Jun 2004
Posts: 1008
Location: CA

Concur with ywilfred's working, should be 18!
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Manager
Joined: 31 Mar 2006
Posts: 160

We want x+y =10, so why cannot we have x=0 and y=10?



Intern
Joined: 14 Jan 2006
Posts: 21

amansingla4 wrote: We want x+y =10, so why cannot we have x=0 and y=10?
bump..
any answer to Aman's Q ?
Or if i use x=0, y=1 then k = 20
i think the question is ambiguous. anyone ?



Senior Manager
Joined: 05 Jan 2006
Posts: 373

easy to take y=0 so for any x even negative integer K will be 10.. what is OA/OE == Message from the GMAT Club Team == THERE IS LIKELY A BETTER DISCUSSION OF THIS EXACT QUESTION. This discussion does not meet community quality standards. It has been retired. If you would like to discuss this question please repost it in the respective forum. Thank you! To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative  Verbal Please note  we may remove posts that do not follow our posting guidelines. Thank you.



NonHuman User
Joined: 09 Sep 2013
Posts: 9128

Re: 10x/x+y) + (20y/x+y) = k, where x, y and k are integers. If
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09 Aug 2018, 19:19
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Re: 10x/x+y) + (20y/x+y) = k, where x, y and k are integers. If &nbs
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09 Aug 2018, 19:19






