4039 pasari total
x=gaini
y=rate
z=gaste
t=curci
x=140 gaini
y-z=19, rezulta ca y=19+z
t=3*z
x+y+z+t=4039 pasari
140+(19+z)+z+(3*z)=4039 (am inlocuit cu ce stim, 140 sunt gaini, 19+z rate si 3*z curci)
140+19+z+z+3z=4039
159+5z=4039
5z=4039-159
5z=3880
rezulta ca z=776 gaste
y=776+19=795 rate
t=3*776=2328 curci