2 pipes can fill a tank in 10 and 20 min if the tank is perfect. But there is…
2025
2 pipes can fill a tank in 10 and 20 min if the tank is perfect. But there is a hole in the tank that can empty it in 30 minutes. If both the pipes are opened simultaneously , how long will it take to fill the tank ?
- A.
60/5
- B.
60/7
- C.
60/9
- D.
60/11
Attempted by 9 students.
Show answer & explanation
Correct answer: B
Solution:
Find each rate (tank per minute): Pipe 1 = 1/10, Pipe 2 = 1/20, Hole = 1/30.
Combined filling rate = 1/10 + 1/20 = 3/20 = 9/60.
Net rate after accounting for the hole = combined filling rate - emptying rate = 9/60 - 2/60 = 7/60 tank per minute.
Time to fill the tank = 1 ÷ (7/60) = 60/7 minutes (approximately 8.57 minutes).
Final answer: 60/7 minutes.