Q117
A solid metallic sphere of radius 15 cm is melted and recast into spherical balls of radius 3 cm each. What is the ratio of the surface area of the original sphere and the sum of the surface areas of all balls?
A.
1 : 5
AnswerB.
5 : 27
C.
1 : 10
D.
3 : 40
Answer: Option A
Solution
Answer: Option A
Solution:
R3 = nr315 × 15 × 15 = n × 3 × 3 × 3
n = 125
(n = number of small spherical balls)