Let's translate the sentences into equations:
One number is 20 more than another: [tex]x=20+y[/tex]
If the greater number is increased by 4: [tex]x+4\ldots[/tex]
The result is five times the smaller [/tex]\ldots=5y[/tex]
So, we have the following system:
[tex]\begin{cases}x=20y\\x+4=5y\end{cases}[/tex]
Use the expression for x given by the first equation to solve the second:
[tex]x+4=5y \iff 20+y+4 = 5y \iff 24= 4y \iff y = 6[/tex]
which easily implies
[tex]x=y+20 = 26[/tex]