Question

y varies directly with x, and y = 2 when x = 5.

What is the value of x when y = 15?

A. x = 25
B. x = 10
C. x = 6
D. x = 37.5

Answer 1

We can see that y has to be multiplied by 2.5 in order to get x.
So...
15 * 2.5 = 37.5
The answer would be D!

Answer 2

2/5 = 15/x

cross multiply
x =6