When two pipes fill a pool together, they can finish in 5 hours. If one of the pipes fills half the pool then the other takes over and finishes filling the pool, it will take them 18 hours. How long will it take each pipe to fill the pool if it were working alone?
Explanation: If you look carefully, you can see that the answer is the second condition as well. If one pipe did half, then the other pipe took over and that took 18 hours, that means that it equals one pipe filling the pool continuously by itself. :)
