Math
posted by Utkarsh .
one tank have 550 liter oil 2/5 part oil is sold and 1/5 is poured from tank how many oil is remaining in the tank

You have 550 litres of oil. 1/5 is 0.2, so you can do 550 * 0.2 with a calculator to get 110.
110 * 2 = 220, so you sold 220 litres.
You also poured 110 litres out.
This means in total, you lost 330 litres.
550  330 = 220 litres remaining.