Question

T3) The value of y varies directly with x, and y =6 when x =18 Find y when x = 12

Answer 1

If y varies directly with x means that there is going to be a constant of proportionality between them in the form

`y=kx`

use the data of y=6 when x=18 to find the constant of proportionality

`\begin{gathered} 6=k\cdot18 \\ k=(6)/(18) \\ k=(1)/(3) \end{gathered}`

use k to find the value of y when x=12

`\begin{gathered} y=(1)/(3)(12) \\ y=4 \end{gathered}`