[tex]p\%=\frac{p}{100}\\\\A.\ 45\%=\frac{45}{100}=\frac{45:5}{100:5}=\boxed{\frac{9}{20}}\\\\B.\ \begin{array}{ccc}45\%&-&27\\100\%&-&x\end{array}\ \ \ \ |cross\ multiply\\\\\\45\cdot x=27\cdot100\\45x=2700\ \ \ \ |divide\ both\ sides\ by\ 45\\\boxed{x=60}\\\\C.\ 60-27=\boxed{33}[/tex]