if there is 3 liters of air in the lungs& 2/10 of it is oxygen,then how many milliliters of oxygen arein lungs

Answer 1

Here's how to calculate it:
From conversion table: 1 liter = 1,000 milliliters
3 liter = 3 x 1,000 ml = 3,000 ml
... that's the volume of air in the lungs.
If 2/10 of that volume is oxygen, then:
2/10 x 3,000 ml = 600 ml

Answer 2

600ml