# Thread: Calculus Word Problem

1. ## Calculus Word Problem

Water is leaking out of an inverted conical tank at a rate of 7000 cm3/min at the same time that water is being pumped into the tank at a constant rate. The tank has height 6 m and the diameter at the top is 4 m. If the water level is rising at a rate of 20 cm/min when the height of the water is 2 m, find the rate at which water is being pumped into the tank.

2. Originally Posted by kashifzaidi
Water is leaking out of an inverted conical tank at a rate of 7000 cm3/min at the same time that water is being pumped into the tank at a constant rate. The tank has height 6 m and the diameter at the top is 4 m. If the water level is rising at a rate of 20 cm/min when the height of the water is 2 m, find the rate at which water is being pumped into the tank.

$\frac{r}{h} = \frac{2}{6}$

$r = \frac{h}{3}$

$V = \frac{\pi}{3}\left(\frac{h}{3}\right)^2 h$

$V = \frac{\pi}{27} \cdot h^3$

$\frac{dV}{dt} = \frac{\pi}{9} \cdot h^2 \cdot \frac{dh}{dt}$ = (volume rate in) - (volume rate leaking out)

mind your units

3. can u be more specific
thanks

4. Originally Posted by kashifzaidi
can u be more specific
thanks
I think solving the problem short of substituting the given numerical values is specific enough.