(This is an old chestnut of a puzzle, but with a slight twist)
It takes six minutes for just the cold tap to fill my bath with water.
The hot tap fills the bath at the same rate, but unfortunately (due to some strange plumbing) after the hot tap has been running for three minutes its supply of water shuts off for a full two and a half while the hot water tank refills and reheats - after the two and a half minutes, the hot tap commences dispensing water once again.
With the plug pulled out, a full bath empties (at a uniform rate) in only four minutes.
With the hot water tank full and the plug pulled out, how long will it take my bath to fill if I turn both taps on?
well, in my world, the tub would never fill, because the amount of water coming out is dependant on the size of the pipe, which produces a different situation than the one in the puzzle.
With the hot fully on and the cold fully off, the pipe is transferrring water at the pipes maximum rate. The same is said for the reverse situation. Turning both taps fully on will also transfer water at the pipes maximum rate, which is slower than the empty rate. (The only thing that will change is the temperature of the water running through the pipe, as the relative mixture will change when the hot tank is empty.)
Another pitfall is that the water draining is not at a constant rate. The water pressure has a dramatic effect on the draining rate... (i.e., the bath is emptying faster as it fills more)
Darn real world limitations...
No Subject
