[tex]\sf \{x,y\}~d.p~\{4,5\} \longrightarrow \frac{x}{4}= \frac{y}{5} \longrightarrow 5x=4y~deci~x= \frac{4y}{5} \\ \\
\frac{p*x}{100}=y \\ \\
\frac{p* \frac{4y}{5}}{100}=y \\ \\
\frac{4py}{5}=100y \\ \\
4py=500y \\ \\
p= \frac{500\not y}{4\not y} \\ \\
p= \frac{500}{4} \\ \\
\boxed{\sf p=125 \%} [/tex]
