13.068. The working hour of masters $A$ and $B$ is paid differently, but both masters worked the same number of hours. If $A$ had worked one hour less, and $B$ had worked five hours less, then $A$ would have earned 720 rubles, and $B$ 800 rubles. If, on the contrary, $A$ had worked five hours less, and $B$ had worked one hour less, then $B$ would have earned 360 rubles more than $A$. How much did each master actually earn?
## Solution:

Let the masters have worked $x$ hours. If $A$ had worked 1 hour less, he would have earned $\frac{720}{x-1}$ rubles per hour; if $B$ had worked 5 hours less, he would have earned $\frac{800}{x-5}$ rubles per hour. According to the condition, $\frac{800}{x-5}(x-1)-\frac{720}{x-1}(x-5)=360$, from which $x=25$. In reality, $A$ earned $\frac{720}{25-1} \cdot 25=750$ rubles, and $B$ earned $\frac{800}{20} \cdot 25=1000$ rubles.

Answer: 750 and 1000 rubles.