What is the ratio of x to y?

[ehu405]

Hi - I ran into the following problem on my first MGMAT CAT. Seems like the answer is making assumptions that are not stated anywhere in the question?

What is the ratio of x to y?

(1) 5x = 2y

(2) 2y = 7x - 8


MGMAT says A is sufficient. However, that automatically assumes that Y does not equal to 0, which is not stated anywhere. If Y = 0, then x/y would be undefined. Is this an error or have I completely lost my mind?

[anand0408]

hey ehu405....lost mind i would say....joking!

Actually you have a valid question, but the fact is that they have given us the 2 sides of the equation. So its only a question of cross multiplying.

[ehu405]

Right but doesn't that preclude Y from being 0 when nowhere in the problem is it stated that Y doesn't equal 0?

[Ben Ku]

Because the ratio can be expressed as a fraction, it is understood that neither part is zero. Ratios compare two quantities, and you don't compare something with zero.

So if we are finding the ratio of x to y, we assume that neither x nor y is zero. Hope that helps.

[tarek.naim1]

Because the ratio can be expressed as a fraction, it is understood that neither part is zero. Ratios compare two quantities, and you don't compare something with zero.

So if we are finding the ratio of x to y, we assume that neither x nor y is zero. Hope that helps.

Hello Ben,
I am still not clear on the assumption part. the equation 5x=2y has a possible solution in which x=y=0. If I understood you correctly, you said that since the question is asking us to find x/y, we automatically assume that x&y is not equal to zero?
hard to think about it this way, especially on a DS question.

[jnelson0612]

Because the ratio can be expressed as a fraction, it is understood that neither part is zero. Ratios compare two quantities, and you don't compare something with zero.

So if we are finding the ratio of x to y, we assume that neither x nor y is zero. Hope that helps.

Hello Ben,
I am still not clear on the assumption part. the equation 5x=2y has a possible solution in which x=y=0. If I understood you correctly, you said that since the question is asking us to find x/y, we automatically assume that x&y is not equal to zero?
hard to think about it this way, especially on a DS question.

Tareq, that is correct.

Since the problem is asking you to find the ratio of x to y, you can assume that neither x nor y is zero, as Ben stated earlier.

Thank you,