x-suma initiala
I zi a cheltuit: x-x/6=(6x-x)/6=5x/6
0,3=3/9=1/3
II zi a cheltuit: 5x/6-(5x/6)·1/3=5x/6-5x/18=(15x-5x)/18=10x/18=5x/9
0,25=25/100=1/4
III zi a cheltuit: 5x/9-(5x/9)·1/4=5x/9-5x/36=(20x-5x)/36=15x/36=5x/12
5x/12=81
x=(81·12)/5
x=194,4 lei suma initiala
I zi a cheltuit: 1944/10x1/6=1944/60=32,4 lei
II zi a cheltuit: (194,4-32,4)x1/3=162/3=54 lei
III zi a cheltuit: (194,4-32,4-54)x1/4=108/4=27 lei
verificare
194,4-32,4-54-27=81 lei ramane
-------------------------------------------succes!---------------------------------------------