Question

7. A tap can fill a tank in 4 hours and another tap
can fill it in 6 hours. Two outlet pipes can empty
the tank in 8 hours and 12 hours respectively.
All four were opened and allowed to run for
3 hours. Then the taps were closed. How long
will the outlet pipes take to empty the tank?​

Answer 1

Answer:

both outlet pipes can empty the tank in 3hrs