Question

Un elev a cheltuit o suma de bani in cinci zile. Stiind ca in prima zi a cheltuit o cincime din suma,a doua zi un sfert din rest,a treia zi o treime din noul rest, a patra zi o doime din noul rest si a cincea zi 3000 lei,aflati cat a cheltuit in fiecare zi. Va rog sa-mi explicati.

Answer 1

S=suma
I zi :  a cheltuit (1/5)S
ramane: S-(1/5)S=(4/5)S

II zi: a cheltuit (4/5)S:4= (1/5)S
ramane (4/5)S-(1/5)S=(3/5)S

III zi: a cheltuit (3/5)S:3=(1/5)S
ramane: (3/5)S-(1/5)S=(2/5)S

IV zi: a cheltuit (2/5)S:2=(1/5)S
ramane : (2/5)S-(1/5)S=(1/5)S
V zi : 3000 lei (ramasi de ieri) =(1/5)S

observam ca in fiecare zi a cheltuit aceeasi suma : (1/5)S=3000 lei

daca te intereseaza cat avea la inceput = 3000x 5 zile= 15.000 lei