P. 4424. A 20-litre plastic can contains petrol. The can is floating on the surface of the water of a lake, such that one-third of the volume of the can is out of the water. The mass of the empty can is 0,78 kg. The density of petrol is 720 , the density of plastic is 1300 . Approximately how many litres of petrol are there in the can?
Deadline expired on 10 April 2012.