The values of x and y vary directly. Hence, we can write
[tex]y=kx[/tex]
Here, k is the constant of proportionality.
Substitute x=0.1 and y=0.9 in the above equation and solve for k.
[tex]\begin{gathered} 0.9=k\times0.1 \\ k=\frac{0.9}{0.1} \\ k=9 \end{gathered}[/tex]
Put the value of k in y=kx.
Therefore, y=9x.
