How Long will It Take to Either Completely Filled or Emptied as the Case may be?
A tap can fill a tank kin 16 min and another can empty it in 8 min. If the tank is already ½ filled and both the taps are opened together. Will the tank be filled or emptied? How long will it take to either completely filled or emptied as the case may be?
- Emptied in 16 min
- Filled in 8 min
- Emptied in 8 min
- Filled in 12 min
Answer: (3) Emptied in 8 min
A tap can fill a tank = 16 min
Therefore, A tap can fill in a min = 1/16
B tap can fill a tank = 8 min
Therefore, B tap can fill a min = 1/8
A and B can empty a tank in a min = 1/8 – 1/16
= (2 – 1)/16
Therefore, A and B can empty a tank = 16 min
If the tank is all ready 1/2 filled.
Then, half tank will be empty = (1/16) 1/2
So, the tank emptied in 8 min.
Hence, the answer is (3) Emptied in 8 min.