help me with this math problem?

Question

the radius of a sphere is increasing at a rate of 5cm/min. When the radius is 10cm, the rate of increase , in cm3(cube)/min, of the sphere is?

Answer 1

V = 4/3*pi*r^3 so dV/dt= dV /dr*dr/dt = 4pir^2*dr/dt.
Ar the given point r=10 and dr/dt=5 so
dV/dt= 400*pi*5= 2000pi cm^3/min

Answer 2

Maths is really a burden ....... i hate Maths ......