Cati litri de benzina are in total in rezervor ?
12 litri + 35 litri = 47 litri de benzina
9 litri ...................100 km
x litri ...................400 km
_______________________
x = 9 × 400 : 100 = 36 litri de benzina consuma dupa un traseu de 400 km
47 l - 36 l = 11 litri de benzina vor ramane