Hey there!
I believe the answer to your question is 47.21 ml of oxygen are in the 55 ml sample of sea water.
To get this, you can do 0.8584 x 55 = 47.212, because you want to find 85.84% of 55, to know how much oxygen is in the sample. Then, you round it to the nearest hundreth.
Hope it helps! Have a great day! Do tell me if I'm mistaken.
