Question

If y varies directly as x, and y is 18 when x is 5, which expression can be used to find the value of when x is 11?

Answer 1

`(18)/(5)` (11)

Explanation:

If it varies directly, you need to find k, the constant of proportionality.

This is done by plugging the values in for x & y that are known.

y = kx

18 = k(5)

`(18)/(5)` = k

Now solve for y when x is 11.

y =
`(18)/(5)` (11)

y = 39.6