a, b, c are integers. Is their product abc equal to 0? 1.

Question

a, b, c are integers. Is their product abc equal to 0?

1. a^2 = 2a

2. b/c =   - 1


A. Statement (1) ALONE is sufficient, but Statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but Statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.

ronneyc · Answer

Hi,

Statement 1 alone is not sufficient because (a) could be equal to zero or not. We also do not know about (b) and (c).

In statement 2 note that (a^2 + 2ab + b^2) = (a+b)^2
which makes   - 1 = 1 - 1 = 0 
so we know now that b/c = 0. Since a,b,c are integers we conclude that b=0.

Thus Statement 2 alone is sufficient. 
Answer is B

hidalgo01 · Answer

I would say answer is B.

Since to hold true B/C = 0 ; B =0

Ravshonbek · Answer

I could not figure out anything to make the answer E. it is B.

bkk145 · Answer

E.

(1) a can be 0 or 2
INSUFFICIENT

(2) b/c =   - 1
=> b = c*  - c
=> b+c = c* 
=> (a+b)^2 * (b+c) = c*(a+b)^2
=> (a+b)^2 * (b+c) - c*(a+b)^2 = 0
=> ((a+b)^2) * (b) = 0
This gives b=0 or a=-b
INSUFFICIENT

Together, if a=0, then b=0
if a=2, then b=-2
INSUFFICIENT since we don't know c.

GMATBLACKBELT · Answer

This has to be E.


S1: a could be 2 or 0 insuff.

S2: b/c (when worked out) = 0 (not -1 as I originally posted)

anyway its still insuff.

ywilfred · Answer

St1:
Could be a = 0, a = 2. Insufficient.

St2:
b/c =   - 1
b/c = 0

So b = 0. a*b*c = 0.
Sufficient.

Ans B

Vlad77 · Answer

It's E
1) a=0 or a=2 => insufficient
2) b/c=0 (or b=0) only if (a+b) does not equal to 0 (a does not equal to -b), since we know nothing about a => insufficient
1&2) if a=0 and b=0 we forbid the statement that a should not equal to -b
so insufficient

beckee529 · Answer

this was tricky one.. i fell for the trap and had B at first. thanks for the good explanation

ethan_casta · Answer

I don't know how anyone could think the answer is e. 

statement 1: a = 0, 2. insufficient

statement 2: b = 0. if be = 0, the answer is yes a * b * c = 0



The answer is B very obviously.

pmenon · Answer

I say B.

St. 1 just tells us that a=2 or -2. Nothing bout b or c, so insufficient

St. 2 tells us that b/c = 1-1 =0 . Therefore, b must equal 0. And any product where one of the terms is 0 makes the overall product 0 .

So , statement 2 seems to be enough, and thats what got me to B

a, b, c are integers. Is their product abc equal to 0? 1.

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