(Try not to read this hint unless you’ve already attempted the problem.) Everyone’s numbers for this problem might be different, but the main ideas will be the same.
You have an upside-down cone and water is flowing in and out of it. You’re told that water is being pumped in at a constant rate, and then asked to find what that rate is. At first I think it’d be helpful to consider 
, the function that models the volume of water that’s flowed in at time 
, and 
, the function that models the amount of water that’s flowed out at time . My version of the question says that water is flowing out at 10,000 cubic cm per minute, so that means 
. Since it says that water is flowing in at a constant rate, I’m going to let 
; then my job is to find 
.
If I let 
be the volume of the water that’s actually in the tank at time , then 
, (this assumes that at time 
there is no water in the tank, but this assumption won’t end up mattering) so 
.
Hopefully this set-up is enough to help you get started!
does the units of meters have to be converted int cm?
Hi Nicholas. Indeed. The units should be consistent throughout. Since the answer should be in cm/min, it’s probably a good idea to convert everything given in m to cm.