The ratio of the weights of two spheres is 81 : 64 and the ratio of their weights per cc of material is 3 : 1. The ratio of their radius is?
Answer & explanation
Correct answer: option 1
Weight of sphere = volume × weight per cc
⇒ Volume : r3 : R3
⇒ Weight per cc : 3 : 1
⇒ Weight : 81 : 64
ATQ,
⇒ r3 : R3 = \(\frac{81}{3}\) : 64 = 27 : 64
Hence, r : R = 3 : 4