Q. Two pipes can fill a tank in 4 hours and 6 hours respectively. If both are opened for 2 hours and then the faster pipe is closed, how much time will the slower pipe take to fill the remaining tank?
✅ Correct Answer: (B)
2 hours
Explanation: Work done in 2 hours = 2(1/4+1/6)=5/6. Remaining=1/6 → slower pipe (1/6 per hour) takes 1 hour.
Explanation by: Kanak Sharma
Work done in 2 hours = 2(1/4+1/6)=5/6. Remaining=1/6 → slower pipe (1/6 per hour) takes 1 hour.