fie x suma initiala, vom scrie in functie de x cat a cheltuit Bogdan in fiecare zi:
I) 1/3x+180
II) 1/3[x-(1/3x+180)]+180=2/9x+120
III) 1/3[x-(2/9x+120)]+180=7/27x+140
stiind suma ramasa obtinem ecuatia:
x-(1/3x+180)-(2/9x+120)-(7/27x+140)=480
x-1/3x-2/9x-7/27x-440=480
5/27x=920 => x=920x27/5=4968
x=4968 lei => I) 1/3x+180=1836 lei
II) 2/9x+120=1224 lei
III) 7/27x+140=1428 lei