Answer:
48π
Step-by-step explanation:
Given that,
The radius of the sphere is increasing at a rate of 3cm/minute, [tex]\dfrac{dr}{dt}=3\ cm/minute[/tex]
The volume of a sphere is given by :
[tex]V=\dfrac{4}{3}\pi r^3[/tex]
Differentiating both sides wrt t.
[tex]\dfrac{dV}{dt}=\dfrac{4}{3}\pi \times 3r^2\times \dfrac{dr}{dt}\\\\=4\pi r^2\times \dfrac{dr}{dt}[/tex]
Put r = 2 cm and dr/dt = 3 cm/minute
So,
[tex]\dfrac{dV}{dt}=4\pi r^2\times \dfrac{dr}{dt}\\\\\dfrac{dV}{dt}=4\pi \times 2^2\times 3\\\\\dfrac{dV}{dt}=48\pi[/tex]
Hence, the correct option is (a) "48π".
