If you fully open only the hot tap, then the 10 liter bucket will fill up in 100 seconds, and if you open only the cold

If you fully open only the hot tap, then the 10 liter bucket will fill up in 100 seconds, and if you open only the cold tap completely, the 3 liter jar will fill up in 24 seconds. Determine how long it will take for the 4.5 liter pan to fill with water if open both valves completely.

To solve the problem, let’s find what volume each of the taps fills in 1 second.
If a cold tap fills 10 liters in 100 s, then in 1 s it will fill 10/100 = 0.1 l;
The hot tap will fill 3/24 = 0.125L in 1 second;
Both taps together in 1 second will fill 0.1L + 0.125L = 0.225L.
This means that both taps will fill a 4.5l pot in 4.5 / 0.225 = 20s.