Problems below are about speed of light and Snell's law. Show to me how can I get the correct answer step-by-step.

SPEED OF LIGHT 1. Calculate the speed of light through glycerine which has a refractive index of 1.4729. 2. Calculate the refractive index of an unknown substance where the speed of light through the substance is 1,974x108nvsv. Round off your answer to 2 decimal places. Snell's Law 1. A light ray with an angle of incidence of 35passes from water to air. Find the angle of refraction using Snell's Law. The refractive index is 1.333 for water and about 1.0 for air. 2. A light ray passes from water to diamond with an angle of incidence of 75. Calculate the angle of refraction. The refractive index is 1.333 for water and 2.42 for diamond