$a)$

$10\%=\frac{10}{100}=\frac{1}{10}$

$75\%=\frac{75}{100}=\frac{3}{4}$

$50\%=\frac{50}{100}=\frac{1}{2}$

$600\%=\frac{600}{100}=\frac{6}{1}=6$

$b)$

$\frac{1}{4}=\frac{25}{100}=25\%$

$\frac{1}{2}=\frac{50}{100}=50\%$

$1\frac{1}{2}=\frac{150}{100}=150\%$