I need help with these

Application: ( 1. Ms. Brahmbhatt suspects that the ruby nose-ring she bought is garnet (not nearly as valuable). She takes it to a jeweller who determines that the speed of light through the nose-ring (v) is 1.74 x 10 m/s. If the refractive index (n) of ruby is 1.77 and that of garnet is 1.72, did Ms. Brahmbhatt buy an expensive or cheap nose-ring? (Show your work). (3 marks) 2. As a jeweller, you have a keen eye for rare materials. While at a friend's house, you notice that there is a really big and beautiful stone sitting at the bottom of their fish tank. Being nosy, you decide to shine a beam of light at an angle of 450 through the air, into the water and then into the stone. If you find that the light refracts within the stone at an angle of about 23.5, what is the stone made of (4 marks) Use the information below Medium n Air 1.00 Water 1.33 Plexiglas 1.49 Polycarbonate 1.59 Sapphire 1.77 Cubic Zirconia 2.16 Diamond 2.42