13.075. Two workers together produced 72 parts per shift. After the first worker increased their productivity by $15 \%$, and the second by $25 \%$, together they started producing 86 parts per shift. How many parts does each worker produce per shift after the increase in productivity?
## Solution.

Initially, the workers produced $x$ and $72-x$ parts per shift, and then $1.15x$ and $1.25(72-x)$ parts. According to the condition, $1.15x + 90 - 1.25x = 86$; $0.1x = 4; x = 40; 1.15 \cdot 40 = 46$.

Answer: 46 and 40 parts.