Answer:
Rounding to the nearest minute, it would take 95 minutes, or 1 hour and 35 minutes.
Step-by-step explanation:
Let's convert each time to minutes:
3.2 hours = 192 minutes
80 minutes = 80 minutes
2 hr 20 min = 140 minutes
Next, let's find the least common multiple:
LCM(192, 80, 140) = 6720
So let's say the volume of the tank is 6720 units. The speed of each pump is therefore:
Pump 1 = 6720 units / 192 minutes = 35 units/minute
Pump 2 = 6720 units / 80 minutes = 84 units/minute
Pump 3 = -6720 units / 140 minutes = -48 units/minute
Their combined speed is:
35 + 84 − 48 = 71 units/minute
So the time to fill the tank is:
6720 units / (71 units/minute) = 94.65 minutes
Rounding to the nearest minute, it would take 95 minutes, or 1 hour and 35 minutes.
