If ab ≠0, does a = b? (1) xa = xb (2) x = x2

[rajivranprasad]

can u explain ds question
i am unable to get the explaination given.

[jnelson0612]

can u explain ds question
i am unable to get the explaination given.

If ab ≠ 0, does a = b? (1) xa = xb (2) x = x^2

I assume that the answer is E. Let's take this apart piece by piece.

First, ab does not equal zero means that neither a nor b is zero. Our question is does a=b?

Let's start with statement 2, since it is far easier:

2) x=x^2
That tell us nothing about a or b. Cross off BD.

1) xa=xb
Let's plug in numbers. If x=1, then a=b.
However, is x=0, then a could be any number and b could be any number. When they are multiplied by zero by will become zero, and thus they do not have to be the same. Thus, 1 is insufficient. Cross off 1.

1+2) Let's go back to statement 2. If x=x^2, then x could be 0 or 1. As we saw when we looked at statement 1, because of this a could be equal to b or a might not be equal to b. Insufficient. The answer must be E.

[HemantR606]

Hi Jamie,

But the answer given is 'C'.

I didn't understand the explanation provided too.

What is the correct answer?

[RonPurewal]

Shouldn't be C, unless the original poster transcribed the question incorrectly.

To prove that it's E, just take two cases.
x = 0, a = b = 1: Satisfies both statements, a = b.
x = 0, a = 1, b = 2: Satisfies both statements, a ≠ b.
Done. It's E.

[RonPurewal]

I just tried to look up this question in our database, and I couldn't find it. Are you sure this question is from our CAT test?

If it is"”"”and if the answer is actually given as C, which it really, really shouldn't be"”"”would you mind taking a screen shot of it and posting it?
Thanks.

[kritis686]

[img]file:///Users/kritisood/Desktop/Screenshot%202020-05-01%20at%206.06.13%20PM.png[/img]
its from MGMAT CAT. the answer is provided as E.

[Sage Pearce-Higgins]

Your image doesn't display, but I've found the problem in our database (it's called 'Does a equal b?').

Do you have a question about it?