Refractive index(RI) of glass (µglass)is 1.5
and Refractive index(RI) of water(µwater) is 1.33
Now, RI of glass with respect to water = waterµglass = µglass / µwater = 1.5 /1.33 = 1.127
RI of water with respect to glass = glassµwater = µwater / µglass = 1.33/1.5 = 0.89