How would you use the index of refraction of salt water to find the concentration of a salt solution?

As the salt solution increases its salinity, its refractive index also increases, with decreasing temperature. Through this relationship, the refractive index of salt solution at a constant temperature can be used to determine the concentration of the said solution.

The objects are acted upon by only one force. gravity. mass times the acceleration of gravity (-9.81meters/second squared).