Question

If y varies directly as x, and y=9 when x=8, find y when x=16.

Answer 1

Answer: y=18

Step-by-step explanation:

We see "varies directly", we use:

y=kx

To find k, we use y=9 when x=8:

We plug in what we know.

y=kx

9=k(8)

Simplify

k=9/8

So, our equation is:

`y=(9)/(8)x`

Now, to find y, we use x=16. So,

`\begin{gathered} y=(9)/(8)x \\ =(9)/(8)(16_{}) \\ \text{Calculate} \\ y=18 \end{gathered}`

Therefore, the value of y is 18.