Assuming the question is : How much does x liters/milimeters of oil weigh?
First, we calculate how much mass did the bottle of oil lose : 590 - 400 = 190 (grams)
Since it loses 190 grams after Sophia uses 200 milimeters of oil, 200 milimeters of oil weighs 190 grams (yes.)
-> 1 milimeter of oil weighs : 190/200 = 0.95(grams)
So, to calculate the mass of x *liters* of oil, we take 0,95 x 1000 times x.
For example : To calculate the mass of 22,5 liters of oil, we take 0,95 x 1000 x 22,5 = 21375 (g) or 21.35(kg).