The volume of two spheres are in the ratio 64 : 27. Find the difference of their surface areas if the sum of their radii is 7 cm.
Volume of a sphere
Given Ratio of volumes of two spheres
So, r = 4x and R = 3x
Also given that the sum of radii = 7
⇒ r +R = 4x +3x =7x =7
⇒ x =1
So, r = 4cm and R = 3cm
Surface area of a sphere
Difference in total surface area =