Question

The value of y varies directly with the value of x, and y = 12 when x = 4.

Answer 1

You can basically plug in the numbers for x and y into the options:

A. y/x = 3
12/4 = 3, so this one is right

B. xy = 3
12*4 = 48, so this is wrong

C. x = 3y
3*12 = 36, which is not x (4), so this is wrong

D. y = 3x
3*4 = 12, which is y (12), so this is right

So, A and D are right