Calculus 1- Related Rates Problem

Question

Water is draining from a right cylindrical tank at 5 l/s. The tank has a radius of 4 m and is 15 m tall. How fast is the height of the water changing when the height of the water in the tank is 7 m?

Answer 1

V = πr²h; dV/dt = πr²dh/dt; dV/dt = - 5 l/s = - 0.005 m³/s and h = 7 m, r = 4m;

Because dh/dt = dV/dt/(πr²) = - 0.005m³/s/(π·7²m²) = - 3.25 ·10^-5 m/s =