Question

Yy varies directly as xx. If xx = 5 then yy = 10. Find yy when xx = 13.

Answer 1

`\begin{gathered} when\text{ x = 13:} \\ y\text{ = 26} \end{gathered}`

Step-by-step explanation:

From the question, we have it that y varies directly as x

Mathematically:

`\begin{gathered} y\text{ }\propto\text{ x} \\ y\text{ = kx} \\ \end{gathered}`

where k is the constant of proportionality

When x = 5, y = 10.

Let us calculate k with this:

`\begin{gathered} 10\text{ = k }*5 \\ k\text{ = }(10)/(5)\text{ = 2} \end{gathered}`

Since we have the value of k now, then:

`y\text{ = 2x}`

Now, we want to get the value of y when x = 13

Mathematically, that would be:

`\begin{gathered} y\text{ = 2 }*\text{ 13} \\ y\text{ = 26} \end{gathered}`