## Task 1 - 230831

A completely filled water basin has a large and a small drain valve. If only the large valve is opened, the basin will be empty in exactly one hour; if only the small valve is opened, the basin will be empty in exactly three hours.

How long will it take for the basin to be empty if both valves are opened simultaneously? It is assumed for each of the two valves that the same amount of water flows out in equal time intervals.
If only the large tap is opened, then $\frac{1}{60}$ of the basin's content flows out in each minute; if only the small tap is opened, then $\frac{1}{180}$ of the basin's content flows out in each minute.

If both taps are opened simultaneously, then $\frac{1}{60}+\frac{1}{180}=\frac{4}{180}=\frac{1}{45}$ of the basin's content flows out in each minute. Thus, the basin will be empty after exactly 45 minutes if both taps are opened simultaneously.