1. The problem statement, all variables and given/known data A water tank is in the shape of an inverted conical cone with top radius of 20m and depth of 15m. Water is flowing into the tank at a rate of 0.1m^3/min. (a) How fast is the depth of water in the tank increasing when the depth is 5m? Water is now leaking from the tank at a rate that depends on the depth h, (h= height of water in the tank) this rate is 0.1h^3/min. (b) How fast is the depth of water in the tank changing when the depth is 5m? (c) How full can the tank get? 2. Relevant equations 3. The attempt at a solution Ok for part A: Tan(angle) = 20/15 = 3/4 So i got a formula for r.... r = 4/3 h Which i put into the formula for the volume of a cone and got: V = 16pi/27 * h^3 and then differentiated V with respect to time. dV/dt = 16pi/27 * (3h^2)dh/dt and i know h and dV/dt so i subbed those in and got dh/dt = 7.1697 * 10^(-4) m/min which i'm pretty sure is right. Now I'm not sure how to do part b. Do I set dV/dt as 0.1 - 0.1h^3 and then just do the same thing? Or is this wrong. Also, what about part c? I tend to get a bit lost with these sorts of wordy questions. Please help.