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Fractions

by Aman verma » Thu Aug 11, 2011 12:26 pm
Q: Let there be a fraction whose denominator is one less than the square of its numerator. If we add 2 to both the numerator and denominator, the fraction will exceed to 1/3 and if we subtract 3 from the numerator and denominator the fraction will lie between 0 and 1/10. The actual fraction is :

a)3/8

b)4/17

c)5/24

d)7/48

e)None of these
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by GmatKiss » Thu Aug 11, 2011 12:46 pm
IMO:E, if this is correct i shall explain! :)
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by vini1612 » Thu Aug 11, 2011 1:41 pm
Answer: E
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by GmatKiss » Thu Aug 11, 2011 2:00 pm
given fraction = x/(x^2)-1

1)If we add 2 to both the numerator and denominator, the fraction will exceed to 1/3
2)if we subtract 3 from the numerator and denominator the fraction will lie between 0 and 1/10

a) satisfies 1, but not 2
b) does not satify 1
c) does not satify 1
d) does not satify 1
e) Answer
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by pinchharmonic » Thu Aug 11, 2011 4:11 pm
any nifty ways this can be done without a heuristic approach? ie using the algebra and figuring it out?
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by Aman verma » Fri Aug 12, 2011 6:00 am
OA[spoiler]e)[/spoiler].But what will be the actual fraction that satisfies the given conditions.
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by Frankenstein » Fri Aug 12, 2011 9:57 am
If we add 2 to both the numerator and denominator, the fraction will exceed to 1/3
Hi,
I don't understand this part. Could any one explain this.
Cheers!

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by tpr-becky » Fri Aug 12, 2011 11:00 am
The best approach is to check each answer with each condition. you can do that quickly by cross multiplying to compare the fractions.

For example: 3/8 = 3/9-1 (yes)
(3+2)/8+2 > 1/3 No

5+2/24+2 > 1/3? 7/26 > 1/3 - cross multiply upwards 7 * 3= 21, 26 * 1 = 26 - thus 1/3 is bigger.

hope that helps
Becky
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The Princeton Review
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