Two spherical nuclei have mass numbers 216 and 64 with their radii R_1 and R_2 respectively. The ratio, R_1/R_2 is equal to?

Correct option is A. 3:2
The relation between radius R of nuclei and mass number A is given by R = R₀A^(1/3) where R₀ = empirical constant
thus R₁/R₂ = A₁^(1/3) / A₂^(1/3) = (216)^(1/3) / (64)^(1/3) = 6 / 4 = 3/2 = 3:2