Question

Un elev a cheltuit o suma de bani in 5 zile. stiind ca in prima zi a cheltuit 1 supra 5 din suma,a doua zi 1supra 4 din rest,in a treia zi 1 supra 3 din
noul rest,a patra zi 1 supra 2 din noul rest si a cincea zi 3000 lei,aflati cat a cheltuit in fiecare zi

Answer 1

x-suma initiala
I zi:   x-x/5=(5x-x)/5=4x/5
II zi:  4x/5-1/4·4x/5=4x/5-x/5=3x/5
III zi:  3x/5-1/3·3x/5=3x/5-x/5=2x/5
IV zi: 2x/5-1/2·2x/5=2x/5-x/5=x/5
x/5=3000
x=3000·5
x=15.000 lei

I zi  : 15000·1/5=3000 lei 
II zi    (15000-3000)x1/4=12000/4=3000
III zi:  (12000-3000)·1/3=9000/3=3000
IV zi  (9000-3000)·1/2=6000/2=3000
V zi:  3000
3000+3000+3000+3000+3000=15000·