x% = x/100
So
22.5% = [tex]\sf{\frac{22.5}{100}}[/tex]
Multiply 2 on both sides:
[tex]\sf{\frac{22.5\times2}{100\times2}=\frac{45}{200}}[/tex]
Divide by 5 on both sides:
[tex]\sf{\frac{45\div5}{200\div5}=\frac{9}{40}}[/tex]
So your final answer is [tex]\boxed{\sf{\frac{9}{40}}}[/tex]
