Question

Dintr-o suma un elev a cheltuit jumatate;a doua oara jumatate din suma ramasa,iar a treaia oara un sfert din noul rest si a constatat ca i-au mai ramas 891 lei.Ce suma a avut initial?

Answer 1

x-[x - (x-x/2) :2]:4=891 |×4
4x-x+(x-x/2):2=3564
3x+(x-x/2):2=3564 |×2
6x+x-x/2=7128
7x-x/2=7128
14x/2-x/2=7128
(14x-x)/2=7128
13x/2=7128
13x=7128×2
x=14256:13
x=4752 lei