smc

Since the worker receives a $20$% cut in wages, his present wage would be $\frac{4}{5}$ of the original wage before the cut. To regain his original pay he would have to obtain a raise of $1$ $÷$ $\frac{4}{5}$ = $1$$\frac{1}{4}$. Therefore, the worker would have to get a $\boxed{\text{25\%}}$ raise to acquire his original pay.