If y varies directly as x and y = 15 when x = 5, find y when x = 10.

Answer 1

Hello Audrey,

Since y varies directly with x, the ratio y/x is constant.

y = 15 when x =5 means the ratio y/x = 15/5 = 3

That ratio is the same when x =10. so:

3 = y/10

From there, you would multiply both sides by 10 and get the answer for y.