A cistern has one inlet, L and one inlet, M. L takes 5 hours to fill the empty tank, when M is not open and M takes 8 hours to empty the full tank, if the tank is two fifth full, how much time will it take to fill the tank completely when both L and M are opened simultaneously? (in hours)
Correct Answer: 8 hours
Explanation:
If the tank is 2/5th full, then remaining empty tank will be = 1-2/5=3/5th
L and M can fill the empty tank in = (5*8)/(8-5)=40/3 hours
