Bunuel wrote:

saurabhgoel wrote:

35. If y ≠ 3 and 2x/y is a prime integer greater than 2, which of the following must be true?

I. x = y

II. y = 1

III. x and y are prime integers.

(A) None

(B) I only

(C) II only

(D) III only

(E) I and II

I dont know the OA ? So please help ?

My pick is (A)

Note that we are asked "which of the following MUST be true, not COULD be true. For such kind of questions

if you can prove that a statement is NOT true for one particular set of numbers, it will mean that this statement is not always true and hence not a correct answer.

So we should try to make the listed statements not true for some x and y (which satisfy y≠3 and 2x/y=prime>2).

I. x = y --> not necessarily true: x=3 and y=2 (2x/y=3=prime>2);

II. y=1 --> not necessarily true: x=3 and y=2 (2x/y=3=prime>2);

III. x and y are prime integers --> not necessarily true: x=10 and y=4 (2x/y=5=prime>2).

Answer: A.

Dear bunuel

can't we go have another approach

by considering the options from 1st to 3rd

and see if 2x/y is not a prime no >2

as below

I. x = y --> then 2x/y=2 which is not greater then 2 so can't be true

II. y=1 --> then 2x/y=2 which is also not greater then 2 so can't be true

III. x and y are prime integers --> then this value will be fractional only so cant be an INTEGER so can't be true

hence A is the answer

please enlighten me for this approach

Regards

Puneet

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