Hi !
Here is an alternate approach-
Use the answer choices to your advantage.
GMAT Track of thoughtAll answer choices report values of y OperationLet me
pick C.If y= 1/2 then from xy= 4,substituting y= 1/2 , we have x*1/2=4 or x=8
With y=1/2 and x=8 x/y = 16 and is NOT equal to 36. Eliminate.
You can eliminate D and E also since they would provide values smaller than 36 as values of y keeps increasing.
For D,
If y=2, then with xy=4, x*2=4 =>x=2
With x=2,y=2, x/y = 1 and is NOT equal to 36
For E,
If y=3, then with xy=4, x*3=4=>x=4/3
With x=4/3, y= 3, x/y =(4/3)/3 =4/9 and is NOT equal to 36
For A,If y=1/6 then with xy =4, x*1/6=4=>x=24
With x=24, y=1/6 , x/y = 24/(1/6) = 144 and is NOT equal to 36
Option B is the correct choice,
For B,If y = 1/3, then with xy=4, x*1/3 =4 =>x=12
With x=12,y=1/3 => x/y = 12/(1/3)=36
GMAT Tip:Testing values is a good strategy on GMAT, specially when the answer choices all carry variables.Let me know if this makes sense.
Devmitra Sen
GMAT Mentor