If abc 0, is a 0? (1) 3*a/b 0 (2) b/c^2

Question

If abc ≠ 0, is a > 0?

(1) 3*a/b > 0

(2) b/c^2 < 0

longfellow · Answer

Answer is C

1 tells us that a and b are of the same sign

2 tells us that b is negative as C*c is always positive

both tell us that as b is negative, a is also negative.

Hence C

GMATinsight · Answer

Question : Is a > 0 ?

Statement 1 : 3*a/b > 0

Sign of b is unknown hence sign of a can't be inferred and that can be positive or negative. Hence
NOT SUFFICIENT

Statement 2 : b/c^2 < 0

Since c^2 is a perfect square so that must be positive for all possible values of c
hence, b is negative but the sign of a still can't be inferred. Hence
NOT SUFFICIENT

Combining the two statements  
b is positive and 3*a/b > 0
i.e. a must be positive. Hence
SUFFICIENT

Answer: option C

Hemavakade · Answer

Question stem is asking if a is positive...

statement 1 :
3*a/b > 0

This is possible if both a and b are positive or if both a and b are negative.
Not sufficient.

statement 2 :
b /  c^2  < 0

No information about a. Not sufficient.

combining statement 1 & 2 :
From statement 2 we know  c^2  is always positive so, b is negative..
using this in statement 1 we know a is negative.
This is sufficient to answer the Question.

Answer C

bebu24 · Answer

Both Statements combined are sufficient:

Statement I: 3*a/b > 0
On simplifying:
a/b > 0
This implies either both a and b > 0 or both a and b < 0. Insufficient

Statement II: b/c^2 < 0

Since c^2 will always be positive, b must be less than 0. We don't know anything about a from this. Insufficient

Statement I and II combined:
We know b < 0 , from II,
We know if b < 0 then a <0, from I
Sufficient.

There Option C is the correct answer.

Bunuel

If abc ≠ 0, is a > 0?

(1) 3*a/b > 0

(2) b/c^2 < 0

Kudos for a correct solution.

If abc 0, is a > 0? (1) 3*a/b > 0 (2) b/c^2 < 0

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