Here's a breakdown:

* Speed of light in vacuum: 299,792,458 m/s

* Refractive index of water: 1.33

The refractive index of a medium tells us how much the speed of light is reduced in that medium compared to its speed in a vacuum. We can calculate the speed of light in water using the following equation:

Speed of light in water = (Speed of light in vacuum) / (Refractive index of water)

Therefore:

Speed of light in water ≈ 299,792,458 m/s / 1.33 ≈ 225,000,000 m/s