Two outlet pipes A and B are connected to a full tank. Pipe A alone can empty…
2023
Two outlet pipes A and B are connected to a full tank. Pipe A alone can empty the tank in 10 minutes and pipe B alone can empty the tank in 30 minutes. If both are opened together, how much time will it take to empty the tank completely?
- A.
7 minutes
- B.
7 minutes 30 seconds
- C.
6 minutes
- D.
6 minutes 30 seconds
Attempted by 30 students.
Show answer & explanation
Correct answer: B
Answer:
7 minutes 30 seconds
Explanation:
Let the capacity of the tank be LCM(10, 30) = 30 units.
=> Efficiency of pipe A = 30 / 10 = 3 units / minute
=> Efficiency of pipe A = 30 / 30 = 1 units / minute
=> Combined efficiency of pipe A and pipe B = 4 units / minute
Therefore, time required to empty the tank
if both pipes work = 30 / 4 = 7 minutes 30 seconds