Is a/b0?

Question

Is  \frac{a}{b}>0 , where  b
e{0} ?

(1)  a+b = 0 
(2)  |\frac{a}{b}|>0

self made

niks18 · Answer

Statement 1 : implies  b=-a , So  \frac{a}{b} = \frac{a}{-a} = -1

So we have a  NO  for our question stem.  Sufficient

Statement 2 : mod will always be greater than or equal to  0 . hence  a  and  b  can have any sign

for eg.  a=-2 ,  b=1 ,  \frac{a}{b}<0  but  |\frac{a}{b}|>0

and if  a=b=1 , then  \frac{a}{b}>0  and  |\frac{a}{b}|>0 . So  Insufficient

Option  A

Aussy2000 · Answer

For yes/no DS questions, the correct answer is definitely yes or definitely NO .

Statement 1 is a define No while statement 2 is a definite yes. so the correct answer should be D

shashaankbhat · Answer

IMO A
Stmt 1 tells a and b have opposite signs. So a/b<0. Sufficient

Stmt 2 tells a/b>0 or a/b<0

Posted from my mobile device

niks18 · Answer

Hi  Aussy2000

Can you explain how Statement 2 proves that  \frac{a}{b}>0  ?

amanvermagmat · Answer

Hi Aussy

Statement 2 is actually NOT a definite yes. Its given that |a/b| > 0 or modulus of a/b is positive. For any non-zero number, its modulus will be positive only.

We can have say a=b=2, and so a/b = 2/2 =1 and |a/b| = 1. Here a/b > 0 and |a/b| is also > 0

But we can also have say a=-2 and b=2 and so a/b = -2/2 = -1 but |a/b| = 1. So here a/b < 0 but |a/b| >0

So we can't say whether a/b will be positive or negative on the basis of second statement.

Also in GMAT, whenever the answer is D, both statements give the same answer. So its NOT possible to get No from statement 1 and Yes from statement 2. If I ever come across such a case in my practice (different answers from the two statements) I know I am going off somewhere and I recheck.

niks18 · Answer

Hi  chetan2u

Can you explain why option A is incorrect and why C is correct choice here?

chetan2u · Answer

hi..
Typo.. ans is A .. Thanks
Kudos for pointing out

niks18 · Answer

Thanks chetan2u for clarifying. I have been scratching my head for past half an hour to arrive at C

ManishKM1 · Answer

Hi  chetan2u ,

May be not worth asking, still...

From statement A, A+B=0, we could have A=B=0, So 0/0 ---Undefined ..... We don't know its +ve or -ve. Can we definitely arrive at a conclusion?

amanvermagmat · Answer

Hi  chetan2u ,

May be not worth asking, still...

From statement A, A+B=0, we could have A=B=0, So 0/0 ---Undefined ..... We don't know its +ve or -ve. Can we definitely arrive at a conclusion?

Hi

Chetan will be best to answer this, but in my opinion, even if its not specified, we can ignore such things where we know its undefined. so eg - if its given that x/y > 2, we have to assume y not equal to 0, because otherwise the question stem becomes not defined. Similarly here I think we can safely assume that A and B will not be 0, because then A/B will become undefined.

JS1290 · Answer

Hi,

I had a question regarding the original statement. I was wondering if we can multiply b with 0 and can get the final equation as if a>0?

Thank You!

chetan2u · Answer

Hi.. No you cannot cross Multiply till you know that B is Positive.. If b is positive, a/b>0 will mean a>0.. If b is NEGATIVE, first multiply both sides by NEGATIVE to make statements POSITIVE. Here a/b>0 will become a/b<0 if be is NEGATIVE and ao a<0.. Hope it helps you. ManishKM1 , sorry I missed out on your post.. It's ofcourse always better to mention that B is not equal to zero.

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Is a/b>0?

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