Spheres A and B have their radil 40 cm and 10 cm respectively. The ratio of the surface area of A to the surface area of B is Choose the correct choice from the following:
A) 1 : 4  B) 1 : 16  C) 4 : 1  D) 16 : 1  E) None
Solution   Let the radil of A and B be r and R respectively.   Required ratio	= 4Πr2/ 4ΠR2   ‹=› r2 / R2   ‹=› (r/R)2   ‹=›(40/10)2   ‹=› 16 : 1.   Answer 16 : 1
<result>D</result>
Spheres A and B have their radil 40 cm and 10 cm respectively. The ratio of the surface area of A to the surface area of B is