One pipe can fill a tank 6 times faster than another pipe. If both the pipes together can fill the tank in 40 minutes, then in how many minutes will the slower pipe alone be able to fill the tank?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 280.
Given that, time taken by both pipes to fill the tank = 40 minutes
Efficiency of faster pipe = 6 × efficiency of slower pipe
Total work = Efficiency × Time
Let the efficiency of slower pipe be x units/min.
According to the given question,
Efficiency of faster pipe = 6x
Let the total work to be done be 280 units.
⇒ 280 = (x + 6x) × 40
⇒ 7x = 7
⇒ x = 1 unit/min
Time taken by slower pipe to complete the total work = 280/1 = 280 minutes