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DS problem from GMAT club [#permalink]
 14 Aug 2009, 14:58
Question Stats:
0% (00:00) correct
100% (01:14) wrong based on 0 sessions
another DS problem from gmat club: answer seems to be wrong
A certain prime x is divided by 5 to result in a fraction. Then the fraction's numerator is increased by 4 and its denominator is doubled, after which the resulting fraction is reduced. If the denominator of the result is odd, what is x?
. 7
. 5
. 4
. 3
. 2
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GMAT club answer: 2
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but 2 wouldn't meet the criteria shown in the problem. 2/5 = .4 but 6/10 = .6; .6> .4 ("after which resulting fraction is reduced")
This is the 2nd math problem I got where GMAT club answer was not correct. anybody else having the same issue?
Thanks
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Re: DS problem from GMAT club [#permalink]
14 Aug 2009, 15:19
santoshsingh wrote: another DS problem from gmat club: answer seems to be wrong
A certain prime x is divided by 5 to result in a fraction. Then the fraction's numerator is increased by 4 and its denominator is doubled, after which the resulting fraction is reduced. If the denominator of the result is odd, what is x?
. 7
. 5
. 4
. 3
. 2
------------------------
GMAT club answer: 2
-------------------------
but 2 wouldn't meet the criteria shown in the problem. 2/5 = .4 but 6/10 = .6; .6> .4 ("after which resulting fraction is reduced")
This is the 2nd math problem I got where GMAT club answer was not correct. anybody else having the same issue?
Thanks GMAT Club answer is correct. By reducing the question means canceling out of common factor, which in this case is 2.
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Re: DS problem from GMAT club [#permalink]
14 Aug 2009, 15:57
[quote="santoshsingh"]another DS problem from gmat club: answer seems to be wrong
A certain prime x is divided by 5 to result in a fraction. Then the fraction's numerator is increased by 4 and its denominator is doubled, after which the resulting fraction is reduced. If the denominator of the result is odd, what is x?
. 7
. 5
. 4
. 3
. 2
x/5.....x+4/10 for that to be reduced and denom gives odd x has to be devisable by 2 the only even prime is 2 itself thus x is 2
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Re: DS problem from GMAT club [#permalink]
14 Aug 2009, 19:18
In real test, I would have pick up - 2
Just curious why 7 is not the answer 7/5 -> 1 - 2/5 leading to same results as picking up 2.
Or does the fraction implies the has to be less than 1?
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Re: DS problem from GMAT club [#permalink]
15 Aug 2009, 00:55
dolly12 wrote: In real test, I would have pick up - 2
Just curious why 7 is not the answer 7/5 -> 1 - 2/5 leading to same results as picking up 2.
Or does the fraction implies the has to be less than 1? If you take 7, then (7+4)/10 is not reducible as there is no common factor. And no, the fraction need not be less than 1, but the only prime number that satisfies this condition is 2 as its the only even prime no.
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Re: DS problem from GMAT club [#permalink]
15 Aug 2009, 13:34
Only 2 and 4 shall satisfy the given condition. But we need to be sure that x is prime, so we pick 2 as the answer.
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Re: DS problem from GMAT club [#permalink]
15 Aug 2009, 16:16
You can find discussions of many gmatclub tests questions here: gmat-club-tests-master-threads-all-tests-78599.html
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Re: DS problem from GMAT club
[#permalink]
15 Aug 2009, 16:16
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