# The time (t) required to empty a tank varies inversely as the rate (r) of pumping. A pump can empty a tank in 90 minutes at the rate of 1200 L/min. How long will the pump take to empty the tank at 3000 L/min?

##### 1 Answer

May 3, 2016

#### Answer:

#### Explanation:

90 minutes at 1200 L/min means that the tank holds

To empty the tank at a rate of 3000 L/m will take the time of

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Known condition:

So

Thus at

Observe that this is exactly the same as in first principles.