a pool that measures 400.00cm in width and 8.25 meters in length i filled with water and then mixed with the hydrate AL(NO3)3 *5H2o. Also one gallon of crude oil is spilled on top of the pool. Based on this information answer the following questions:

Determine the thickness of the oil in mm
The answer is 1.15x10^-1 mm but I don't know how to get to that answer