It is currently 23 Nov 2017, 02:52

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# If a#-b, is (a-b)/(b+a) > 1?

Author Message
TAGS:

### Hide Tags

Senior Manager
Joined: 08 Jan 2009
Posts: 325

Kudos [?]: 181 [2], given: 5

If a#-b, is (a-b)/(b+a) > 1? [#permalink]

### Show Tags

03 Oct 2009, 21:51
2
KUDOS
7
This post was
BOOKMARKED
00:00

Difficulty:

95% (hard)

Question Stats:

39% (01:53) correct 61% (02:20) wrong based on 134 sessions

### HideShow timer Statistics

If a#-b, is (a-b)/(b+a) > 1?

(1) b^2 > a^2
(2) a-b>1
[Reveal] Spoiler: OA

Kudos [?]: 181 [2], given: 5

Math Expert
Joined: 02 Sep 2009
Posts: 42322

Kudos [?]: 133092 [2], given: 12408

### Show Tags

04 Oct 2009, 07:45
2
KUDOS
Expert's post
2
This post was
BOOKMARKED
If $$a\neq{-b}$$, is $$\frac{a-b}{b+a}>1$$?

Is $$\frac{a-b}{b+a}>1$$? --> is $$\frac{-2b}{a+b}>0$$ --> is $$\frac{b}{a+b}<0$$?

(1) b^2>a^2 --> $$(b-a)(b+a)>0$$, 2 cases:

A. $$b-a>0$$ and $$b+a>0$$ --> sum these two: $$b>0$$. So $$b>0$$ and $$b+a>0$$ --> $$\frac{b}{a+b}>0$$ --> answer to the question is NO;
B. $$b-a<0$$ and $$b+a<0$$ --> sum these two: $$b<0$$. So $$b<0$$ and $$b+a<0$$ --> $$\frac{b}{a+b}>0$$ --> answer to the question is NO;

So, in both cases answer to the question " is $$\frac{b}{a+b}<0$$?" is NO.
Sufficient.

(2) a-b>1 --> a>b. But b/(a+b) can be < or > 0 (plugging numbers a=3, b=1 and a=3 b=-1) so, not sufficient.

_________________

Kudos [?]: 133092 [2], given: 12408

SVP
Joined: 29 Aug 2007
Posts: 2471

Kudos [?]: 857 [0], given: 19

### Show Tags

04 Oct 2009, 19:43
tkarthi4u wrote:
Can some help me how to approach such questions?

If a#-b, is a-b/b+a > 1?
1) b^2 > a^2
2) a-b>1

1) b^2 > a^2
i.e. lbl > a however b could be +ve or -ve so does a.
In either case, a-b/b+a is always -ve. So Suff..

2) a-b>1 or a > b. In this case:
If a and b both are +ve, (a-b)/(b+a) > 1.
If a and b both are -ve, (a-b)/(b+a) < 1. NSF...

So A is it.
_________________

Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT

Kudos [?]: 857 [0], given: 19

Retired Moderator
Status: 2000 posts! I don't know whether I should feel great or sad about it! LOL
Joined: 04 Oct 2009
Posts: 1628

Kudos [?]: 1125 [0], given: 109

Location: Peru
Schools: Harvard, Stanford, Wharton, MIT & HKS (Government)
WE 1: Economic research
WE 2: Banking
WE 3: Government: Foreign Trade and SMEs
Re: If a#-b, is a-b/b+a > 1? [#permalink]

### Show Tags

26 Jan 2012, 09:32
tkarthi4u wrote:
Can some help me how to approach such questions?

If a#-b, is a-b/b+a > 1?

1) b^2 > a^2
2) a-b>1

Bunuel, I have a a doubt:
In statement (1), we have $$b^2 > a^2$$, so this means that $$b>a$$ or $$b<a$$.
Let's pick numbers:
In the first scenario $$(b>a)$$:
A. a=2, b=3, so $$\frac{b}{(b+a)} > 0$$
B. a=-3, b=1, so $$\frac{b}{(b+a)} < 0$$

As you can see, different results. Insufficient. What I am missing? :s
_________________

"Life’s battle doesn’t always go to stronger or faster men; but sooner or later the man who wins is the one who thinks he can."

My Integrated Reasoning Logbook / Diary: http://gmatclub.com/forum/my-ir-logbook-diary-133264.html

GMAT Club Premium Membership - big benefits and savings

Kudos [?]: 1125 [0], given: 109

Math Expert
Joined: 02 Sep 2009
Posts: 42322

Kudos [?]: 133092 [1], given: 12408

Re: If a#-b, is a-b/b+a > 1? [#permalink]

### Show Tags

26 Jan 2012, 10:15
1
KUDOS
Expert's post
1
This post was
BOOKMARKED
metallicafan wrote:
tkarthi4u wrote:
Can some help me how to approach such questions?

If a#-b, is a-b/b+a > 1?

1) b^2 > a^2
2) a-b>1

Bunuel, I have a a doubt:
In statement (1), we have $$b^2 > a^2$$, so this means that $$b>a$$ or $$b<a$$.
Let's pick numbers:
In the first scenario $$(b>a)$$:
A. a=2, b=3, so $$\frac{b}{(b+a)} > 0$$
B. a=-3, b=1, so $$\frac{b}{(b+a)} < 0$$

As you can see, different results. Insufficient. What I am missing? :s

$$b^2 > a^2$$ basically means that $$b$$ is further from zero than $$a$$: $$|b|>|a|$$. So your second example is not valid.

Basically we can have following cases:
----------0--a--b--
-------a--0-----b--
----b--a--0--------
----b-----0--a-----

For all these cases $$\frac{b}{a+b}>0$$.

Hope it's clear.
_________________

Kudos [?]: 133092 [1], given: 12408

Retired Moderator
Status: 2000 posts! I don't know whether I should feel great or sad about it! LOL
Joined: 04 Oct 2009
Posts: 1628

Kudos [?]: 1125 [1], given: 109

Location: Peru
Schools: Harvard, Stanford, Wharton, MIT & HKS (Government)
WE 1: Economic research
WE 2: Banking
WE 3: Government: Foreign Trade and SMEs
Re: If a#-b, is a-b/b+a > 1? [#permalink]

### Show Tags

26 Jan 2012, 10:33
1
KUDOS
Bunuel wrote:
metallicafan wrote:
tkarthi4u wrote:
Can some help me how to approach such questions?

If a#-b, is a-b/b+a > 1?

1) b^2 > a^2
2) a-b>1

Bunuel, I have a a doubt:
In statement (1), we have $$b^2 > a^2$$, so this means that $$b>a$$ or $$b<a$$.
Let's pick numbers:
In the first scenario $$(b>a)$$:
A. a=2, b=3, so $$\frac{b}{(b+a)} > 0$$
B. a=-3, b=1, so $$\frac{b}{(b+a)} < 0$$

As you can see, different results. Insufficient. What I am missing? :s

$$b^2 > a^2$$ basically means that $$b$$ is further from zero than $$a$$: $$|b|>|a|$$. So your second example is not valid.

Basically we can have following cases:
----------0--a--b--
-------a--0-----b--
----b--a--0--------
----b-----0--a-----

For all these cases $$\frac{b}{a+b}>0$$.

Hope it's clear.

Thanks buddy!, where did you study? You are a genius!
_________________

"Life’s battle doesn’t always go to stronger or faster men; but sooner or later the man who wins is the one who thinks he can."

My Integrated Reasoning Logbook / Diary: http://gmatclub.com/forum/my-ir-logbook-diary-133264.html

GMAT Club Premium Membership - big benefits and savings

Kudos [?]: 1125 [1], given: 109

Non-Human User
Joined: 09 Sep 2013
Posts: 15529

Kudos [?]: 283 [0], given: 0

Re: If a#-b, is (a-b)/(b+a) > 1? [#permalink]

### Show Tags

24 Jul 2014, 05:15
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

Kudos [?]: 283 [0], given: 0

Non-Human User
Joined: 09 Sep 2013
Posts: 15529

Kudos [?]: 283 [0], given: 0

Re: If a#-b, is (a-b)/(b+a) > 1? [#permalink]

### Show Tags

15 Jun 2016, 22:43
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

Kudos [?]: 283 [0], given: 0

Non-Human User
Joined: 09 Sep 2013
Posts: 15529

Kudos [?]: 283 [0], given: 0

Re: If a#-b, is (a-b)/(b+a) > 1? [#permalink]

### Show Tags

11 Sep 2017, 06:18
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

Kudos [?]: 283 [0], given: 0

Re: If a#-b, is (a-b)/(b+a) > 1?   [#permalink] 11 Sep 2017, 06:18
Display posts from previous: Sort by