Respostas

2014-08-04T13:32:06-03:00
Regra de 3
se 40----------------80%
     x------------------100%
80x = 4000
     x = 50 litros
2014-08-04T13:32:12-03:00
X----------100
40---------80    meio pelos extremos
80x=4000
x=4000/80
x=50 ITs
espero ter ajudado