Răspuns :
x-x/2+500 cheltuiti dupa prima zi
au ramas x/2-500 , din acestia cheltuie jumatate +500 =>
x/2-500-(x/2-500)/2-500=x/2-(x/2-500)/2-1000=x-x/2+500-2000=x-3000
mai raman dupa a 2 a zi
x-3000-(x-3000)/2-500=2x-6000-x+3000-1000=x-4000 mai raman dupa a 3-a zi
x-4000-(x-4000)/2-500=2x-8000-x+4000-1000=0 =>x=5000
au ramas x/2-500 , din acestia cheltuie jumatate +500 =>
x/2-500-(x/2-500)/2-500=x/2-(x/2-500)/2-1000=x-x/2+500-2000=x-3000
mai raman dupa a 2 a zi
x-3000-(x-3000)/2-500=2x-6000-x+3000-1000=x-4000 mai raman dupa a 3-a zi
x-4000-(x-4000)/2-500=2x-8000-x+4000-1000=0 =>x=5000