A water tank contains 5000 gallons of water and then flows out of the bottom of the tank within 2 hours. Then give you a formula that represents the volume of water left in the water tank after t minutes.

In fact, you can get the answer to (a) through dv/dt.

Then substitute the 30th and 60th generations into the formula of dv/dt, and you can get the answer of (b).

Question (c) asks whether the proportion of water flowing out of the container increases or decreases with the increase of time. You should compare the answers to question (b) and draw a conclusion. Then I want you to ask in a derivative way. I'm not sure about this problem either.

In fact, to find the speed of something requires derivation, that is, using differentiation.