The refractive index

Benzene has an absolute refractive index, $n_{\text{B}}=1.5$‍, at room temperature.

What is the speed of light in benzene, $v_{\text{B}}$‍?
Note: The speed of light in vacuum, $c=3.0\times {10}^8{\displaystyle \frac{\text{m}}{\text{s}}}$‍.