Linear Function

 

The production cost  C of x liters of GrafClean™ liquid soap can be described by a linear function of x, with x ≥ 0, wich graphic is plotted below.  In this conditions, how many liters can one buy with R$ 100,00 ? [Iezzi et al, 2001 - adapted]

[  1.a  |   1.b  |   2.a  |   2.b  |   3.a  |   4.a  |   4.b  |   5.a  |   5.b  |   6.a  |   6.b  |   6.c  |   6.d  |   7.a  ]