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GmatHack DS

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GmatHack DS

by mbamaverick » Fri Mar 20, 2009 9:34 pm
If m and n are negative, is m/n less than 1 ?

1) mn < 1
2) m - n > n

GmatHack says the answer is E but I calculated answer B. What is your answer?
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Source: — Data Sufficiency |
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by cramya » Fri Mar 20, 2009 10:00 pm
Stmt II

m-n > n

Add n to both sides

m > 2n

n=-1/2 m = -1/10

m/n < 1


n=-6 m>-12 so lest say m=-10

m/n>1

INSUFF


Together:

n=-1/2 m = -1/10

m/n < 1

n = - .1 m = -.15

m/n>1

INSUFF

hence e
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by cramya » Fri Mar 20, 2009 10:01 pm
m.n-> negative does not mean m and n are integers(since its not stated explicitly).

May be this is what led u to B

Hope this helps!
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Reply

by mbamaverick » Fri Mar 20, 2009 10:38 pm
I chose B because

2)m-n > n
=> m > 2n
=> m/n > 2

If m/n > 2 then m/n cannot be less than 1, so to me it is sufficient because we get answer NO here
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Re: Reply

by mbamaverick » Fri Mar 20, 2009 10:47 pm
mbamaverick wrote:I chose B because

2)m-n > n
=> m > 2n
=> m/n > 2

If m/n > 2 then m/n cannot be less than 1, so to me it is sufficient because we get answer NO here
I got it now,
sign of m/n will change because m and n are negative
=> m/n < 2
=> insufficient
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by cramya » Fri Mar 20, 2009 10:58 pm
If an algebric approach doesnt come your mind or seem convincing then picking numbers to prove or disprove is a good way to approach some ds questions.


Have all the tools u possibly can and attack each prob with what comes to your mind first and foremost. This way u wont be wasting valuable time...

Just my 2 cents; good luck!

Regards,
CR
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