Labor productivity increased by 25%. By what percentage will the task completion time be reduced?

1) Suppose earlier they produced x parts per shift, and began to produce x + 0.25 * x. Since in the condition it is given that labor productivity increased by 25%, that is, when converting from percent to fraction, it turned out 0.25.

2) Find similar terms. Let’s transform. x + 0.25 * x = 1.25 * x.

3) For convenience, let’s translate 1.25 into a common fraction. We get: 5/4 * x parts per shift.

4) With the new productivity of labor, the same number of parts can be produced in 4/5 shifts, i.e. the task execution time will decrease by 1/5, or 20%.

Answer. decreased by 20%.