Relative permeability and dielectric constant of a medium are 2 and 1.5 respectively. The refractive index of  the medium is 

Velocity of light in vacuum $C_V=\frac{1}{\sqrt{{\mu }_0{\epsilon }_0}}$

Velocity of light in the medium $C_m=\frac{1}{\sqrt{\mu \epsilon }}$

Refractive index of the medium is $n=\frac{C_V}{C_m}=\sqrt{\frac{\mu \epsilon }{{\mu }_0{\epsilon }_0}}=\sqrt{{\mu }_r{\epsilon }_r}=\sqrt{2\times \frac{3}{2}}=\sqrt{3}$