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Re: 2/d= 2-d/d-2 [#permalink]
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Re: 2/d= 2-d/d-2 [#permalink]
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I am not sure mine was the best approach but it did work.

Just by looking at the denominators, we know d will not be equal 0 or 2 because if d = (0 or 2), the denominators would be 0 which is undefined.

What happens if d is a positive number?

if d = 1 then you end up with 2 = -1 which is false.
If d is greater than 2, then 2/d will ALWAYS be a positive number. The numerator (2-d) will ALWAYS be a negative number and the denominator (d-2) will ALWAYS be a positive number. Since a positive number divided by a negative number always equals a negative number, you know d cannot be a positive number since d/2 is positive and 2-d/d-2 is negative.

What if d is less than 0?

When d is a negative number, 2/d will ALWAYS be negative. The numerator (2 - d) will ALWAYS be a positive number. The denominator (d - 2) will ALWAYS be negative. A positive number divided by a negative number will always be negative.

We do not know what d will be, but at least we know it will be a negative number because that is the only way both sides of the equation will have the same sign. Since 0 is more than any negative number, we can conclude quantity b is bigger.

I hope i didn't make a mistake here. If I did, I apologize in advance.
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Re: 2/d= 2-d/d-2 [#permalink]
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Great question.
It was tricky one.
Answer is B.

After solving the equation, we'll get
either d = 2 or d = -2

But d cannot be equals to 2, because the equation will become undefined.

Thus d = -2

So, Quantity B is greater.
Choice B correct.

Originally posted by GREMasterBlaster on 01 Mar 2018, 04:48.
Last edited by GREMasterBlaster on 04 Mar 2018, 01:42, edited 1 time in total.
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Re: 2/d= 2-d/d-2 [#permalink]
great question, thanks, I just unconscionably assumed that it's D, since the d yielded -+2.
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Re: 2/d= 2-d/d-2 [#permalink]
tricky question. I thought we could not do cross multiplication due to being unsure whether denominator was going to be 0 or not. It turns out we need to assume it's not going to be 0.
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Re: 2/d= 2-d/d-2 [#permalink]
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(a-b)/(b-a) is always equal to -1, so it simplifies to 2/d = -1, which means d is negative. Answer B.
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Re: 2/d= 2-d/d-2 [#permalink]
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Carcass wrote:

This question is part of GREPrepClub - The Questions Vault Project



\(\frac{2}{d}= \frac{2-d}{d-2}\)


Quantity A
Quantity B
d
0


A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given.


You can cross multiply as shown above or range fractions to get the answer straight..
\(\frac{2}{d}= \frac{2-d}{d-2}\)..
\(\frac{2}{d}= \frac{-(d-2)}{(d-2)}\)=-1..
So \(\frac{2}{d}=-1\)..
Only possibility is d=-2

Hence B
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Re: 2/d= 2-d/d-2 [#permalink]
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\(\frac{2-d}{d-2}\) will always equal -1.

Try some values for that: Regardless whether positive, negative or 0, it will equal -1 (as both signs are inversed)


So, \(\frac{2}{d}\) = -1
Therefore, d=-2 and -2<0, hence answer B
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Re: 2/d= 2-d/d-2 [#permalink]
why would not the answer be D?
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Re: 2/d= 2-d/d-2 [#permalink]
Nikhil4GRE wrote:
why would not the answer be D?


D) The relationship cannot be determined from the information given.

To show that the answer is D, you must identify two values of d that yield conflicting comparisons (e.g., in one case Quantity A is greater, and in the other case Quantity B is greater)
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Re: 2/d= 2-d/d-2 [#permalink]
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\(\frac{2}{d} = \frac{2-d}{d-2}\)

\(\frac{2}{d} = \frac{2-d}{-(2-d)}\)

\(\frac{2}{d} = -\frac{2-d}{2-d} = -1\)

\(2 = -d\)

\(d = -2\)

Hence, answer is B
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Re: 2/d= 2-d/d-2 [#permalink]
Hi Brent GreenlightTestPrep, question do not state d is positive/negative. Do we not need to concern about this before cross multiplication in this case? Thanks
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Re: 2/d= 2-d/d-2 [#permalink]
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The LHS and the RHS must be equal and d must be different from zero.

In this scenario you can cross multiply regardless
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Re: 2/d= 2-d/d-2 [#permalink]
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Re: 2/d= 2-d/d-2 [#permalink]
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