The Total solution for NCERT class 6-12
A balloon, which always remains spherical has a variableradius. Find the rate at which its volume is increasing with the radius whenthe later is 10 cm.
The volume of a sphere (V)with radius (r)is given by
Rate of change of volume (V) withrespect to its radius (r) isgiven by,
Therefore, when radius = 10 cm,
Hence, the volume of the balloon isincreasing at the rate of 400π cm2.