There can be 2 answers depending the proportionality between y and x
Assuming y is directly proportional to x
\(y=kx\) where k is constant of proportionality
\(8=20k\)
\(k=\frac{8}{20}=\frac{2}{5}\)
\(y=\frac{2}{5}x\)
\(y=\frac{2}{5}*10\)
\(y=4\)
Assuming y is indirectly proportional to x
\(y=\frac{k}{x}\) where k is constant of proportionality
\(8=\frac{k}{20}\)
\(k=160\)
\(y=\frac{160}{x}\)
\(y=\frac{160}{10}\)
\(y=16\)
