Question

If y varies directly as x, and y = 6 when x = 3, find y whenx = 9. y = ?

Answer 1

If y varies directly as x, we can write the following equation:

`(y)/(x)=k`

When x = 3, we have y = 6, so:

`\begin{gathered} (6)/(3)=k \\ k=2 \end{gathered}`

Now, using x = 9, we have:

`\begin{gathered} (y)/(9)=2 \\ y=18 \end{gathered}`

Therefore the answer is y = 18.