Am I incorrect?

[avlumanau]

Hi folks,

I am going over my Veritas GMAT app for iPhone, and came across a question that I thought Veritas did not answer correctly.

The question is: If x>0 and y>0, is (x-a)/(y-a) < (x/y)?
(1) x>y
(2) a>0

According to Veritas, the answer is C, but I think it should be E. Veritas' explanation is as follows:

I. Pick numbers to see whether we can answer the question Yes or No. If x = 4, y= 3, and a = 2, then:

(4-2)/(3-2)= 2/1; 2/1 > 4/3 - (No)

If x = 3, y = 4, and a = 2, then:

(4+2)/(3+2)= 6/5; 6/5 < 4/3 - (Yes)

Not Sufficient

II. Pick numbers to see if we can answer the question Yes or No. The first set of numbers we picked satisfied these conditions and answered the question No.

If x = 3, y = 4, and a = 2, then:

(3-2)/(4-2)= 1/2; 1/2 < 4/3 - Yes

Not Sufficient.

Together. If we combine the statements, we know x > y and a > 0. The first set of numbers we picked satisfied these conditions and answered the question No. There are no solutions that satisfy the conditions x > y and a > 0 and answer the question Yes.

Therefore, we know if x > y and a > 0, then we know the answer to "is (x-a)/(y-a) < (x/y)?" is No. Sufficient.

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However, by my calculation/reasoning, if we were to use the first set of numbers, but change a from 2 to 6, you will have 2/3 on the left hand side, which is indeed smaller than 4/3.

So the answer should be E, if my reasoning above is correct.

I'd be grateful for any views/help from the forum.

Thanks!

[pemdas]

del

[pemdas]

Hi folks,

I am going over my Veritas GMAT app for iPhone, and came across a question that I thought Veritas did not answer correctly.

The question is: If x>0 and y>0, is (x-a)/(y-a) < (x/y)?
(1) x>y
(2) a>0

According to Veritas, the answer is C, but I think it should be E.

The answer to this question cannot be C. The correct answer is E even by picking numbers.

Consider a=2 when x=8 and y=5. All conditions are satisfied: x>0,y>0,x>y,a>0
6/3>8/5
Now, consider a=6 when x=8 and y=5 with the above conditions satisfied
-2<8/5

The method of solution by Veritas doesn't address the minor possibility from 2 statements such as y<a<=x

I submit either Veritas provides wrong answer or you mishandle the OA from the iphone application program.

[hyena1986]

you can find similar problem in the link

https://www.beatthegmat.com/x-y-function ... 04569.html