Determine the solution of the given question

Question- A laboratory dish, 30 cm in diameter, is half filled with a glucose/water solution. One at a time, 0.45 Micro liter drops of oil from a micropipette are dropped onto the surface of the solution, where they spread out into a uniform thin film. As more drops are added, the intensity of 600nm light reflected from the surface decreases. The intensity reaches a minimum after a total of 13 drops have been added. In all questions, assume that the oil's index of refraction is smaller than the glucose/water solution's index.

Part 1- What is the index of refraction of the oil?

Part 2- Express your answer using two significant figures.

I need help to find the index of refraction of the oil.