If m ≠-n, is (m-n)/(m+n)> 1?
(1) n < 0
(2) m > 0
[spoiler]E[/spoiler]
I think the correct answer should be different.
Source Grockit: DS: Inequallity
This topic has expert replies
-
- Senior | Next Rank: 100 Posts
- Posts: 59
- Joined: Sun Mar 11, 2012 8:57 pm
- Location: India
- Thanked: 16 times
- Followed by:1 members
Hi polter,polter wrote:If m ≠-n, is (m-n)/(m+n)> 1?
(1) n < 0
(2) m > 0
E
I think the correct answer should be different.
Pls go th. https://www.beatthegmat.com/fast-way-to- ... tml#467098
Regards,
Shantanu
If you feel like it, hit thanks
-
- Master | Next Rank: 500 Posts
- Posts: 110
- Joined: Wed Feb 22, 2012 11:28 pm
- Location: India
- Thanked: 13 times
- Followed by:1 members
the question says m +n =0 (given m!= -n)
to find if (m-n)/(m+n)> 1?
this can be reduced to (m-n)/(m+n) -1 >0
i.e. -2n/(m+n)>0
option1: n<0
we cannot say anything about the sign of m+n. hence, above expression can be + as well as -
hence, insufficient.
option1: m>0
we cannot say anything about the sign of above expression. hence, above expression can be + as well as -
hence, insufficient.
combine both : n<0 and m>0
the above expression wil be less than zero only if abs(n)> abs(m), which is not given.
hence, both together are insufficient.
Answer, E
Hope it Helps
to find if (m-n)/(m+n)> 1?
this can be reduced to (m-n)/(m+n) -1 >0
i.e. -2n/(m+n)>0
option1: n<0
we cannot say anything about the sign of m+n. hence, above expression can be + as well as -
hence, insufficient.
option1: m>0
we cannot say anything about the sign of above expression. hence, above expression can be + as well as -
hence, insufficient.
combine both : n<0 and m>0
the above expression wil be less than zero only if abs(n)> abs(m), which is not given.
hence, both together are insufficient.
Answer, E
Hope it Helps
Its do or die this time!
Practise, practise and practise.
Practise, practise and practise.
Hi shantanu86/ spartacus1412, thank you for your suggestions.
My confusion was with this: can this expression not be reduced as
(m-n)/(m+n)> 1
=> (m-n)> (m+n)
=> -n > n
=> 0 > 2n
=> 0 > n
Since (1) clearly defines this. Hence A
My confusion was with this: can this expression not be reduced as
(m-n)/(m+n)> 1
=> (m-n)> (m+n)
=> -n > n
=> 0 > 2n
=> 0 > n
Since (1) clearly defines this. Hence A
- Stuart@KaplanGMAT
- GMAT Instructor
- Posts: 3225
- Joined: Tue Jan 08, 2008 2:40 pm
- Location: Toronto
- Thanked: 1710 times
- Followed by:614 members
- GMAT Score:800
Hi!polter wrote:Hi shantanu86/ spartacus1412, thank you for your suggestions.
My confusion was with this: can this expression not be reduced as
(m-n)/(m+n)> 1
=> (m-n)> (m+n)
=> -n > n
=> 0 > 2n
=> 0 > n
Since (1) clearly defines this. Hence A
Whenever you see inequalities and variables, alarm bells should go off in your head and your internal warning system should be shouting "DANGER DANGER DANGER!!!"
Remember this key difference between equations and inequalities:
When you multiply or divide both sides of an inequality by a negative number, you flip the inequality.
With that rule in mind, here's the mistake you made: you divided both sides by (m+n) without knowing whether that term was positive or negative.
Stuart Kovinsky | Kaplan GMAT Faculty | Toronto
Kaplan Exclusive: The Official Test Day Experience | Ready to Take a Free Practice Test? | Kaplan/Beat the GMAT Member Discount
BTG100 for $100 off a full course