Is |a|=b-c ? (1) a+c b (2) a

Question

Is |a|=b-c ?

(1) a+c≠b

(2) a<0

saurabhkowley18 · Answer

I think the ans is A
Statement 1 is sufficient as the condition a+c not equal to b is possible only is a is negative.
Statement is insufficient as it gives no info about b and c

Value · Answer

I think its C.

1) a+c≠b but may be -a+c=b so not sufficient

2) a<0 insuffcient

Combine a+c≠b and -a+c≠b sufficient

lumone · Answer

I see it this way:

|a|=b-c?
If a> 0, then the question is: a=b-c?
If a<0, then the question is: a=c-b?

(1) a+c≠b
a≠b-c
not sufficient, we need to know whether a>0 to answer that question.

(2)
a>0, but we don't know anything about the relationship between a,b and c

Together, A<0. Therefore the question is: Is a=c-b? And (1) does not tell us that.

My answer is therefore E: Problem the OA is C.

Either I am wrong or the OA is wrong. Would anyone know?

Oski · Answer

Answer is (E)

Statement (1) is insufficient since it just gives us a value a is not equal to: a≠b-c (but a could be anything else than b-c ! including c-b which could be negative or anything else)

Statement (2) is insufficient since it just gives us the sign of a: a<0 (but a could be any negative number! including -|b-c| and all the other negative numbers)

(1) and (2) are insufficient together too since a could be any negative number different than b-c (if b-c is ever negative, which we don't know and in which case |a|=b-c makes no sense).

But if (1) was a+b≠c, then we would have been able to answer the question (answer would have been (C))

scthakur · Answer

I will go with E.

Stmt 1: a + c does not equal b. That means, a does not equal b-c.. Insufficient.

Stmt 2: a < 0. Insufficient.

Combining both, a can still not equal b-c. Insufficient.

saurabhkowley18 · Answer

Hi can you explain how a+b not equal to c is would ans the Q ?

Oski · Answer

If the question was:
 Is |a|=b-c ?

(1) a+b≠c

(2) a0)

(1) tells us a≠c-b

==> we can conclude a = something else i.e. |a|≠b-c

Is |a|=b-c ? (1) a+c b (2) a<0

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards