Răspuns
Explicație pas cu pas:
S = suma de bani
Prima zi: a cheltuit 40S/100
Au ramas 100S/100 - 40S/100 = 60S/100
A doua zi a cheltuit 60/100*60S/100 = 36S/100
In primele doua zile a cheltuit 40S/100 + 36S/100 = 76S/100
Au ramas pentru a treia zi 100S/100 - 76S/100 = 24S/100
40S/100 - 24S/100 = 40
16S/100 = 40
S = 40*100/16 = 250 lei