Taps fill a tank and drains empty it: the time to fill is the litres still needed divided by the net flow, taps minus drains, in litres a minute. A pipe that splits in two sends half to each branch. Tanks joined at the bottom settle at one level once the valve opens: all the water, shared over all the width. Every square is 1 m by 1 m, and the tanks are all equally deep.
3:00 on the clock, and it only runs while a question is on screen.
Questions get harder as you answer correctly and easier when you miss.
You start at the first level.
Until your first miss, every right answer jumps a whole band. After it, three right answers in a row jump a band, and a miss drops one.
A right answer scores the question's points; a wrong one costs half as many. Guessing does not pay.