Question

in trei zile , o persoana cheltuieste o suma de bani : in prima zi cheltuieste un sfert din suma , a doua zi jumatate din suma , iar a treia zi ultimii 375 lei.Ce suma a cheltuit in trei zile ?

Answer 1

S-suma de cheltuit
prima zi :S/4
a doua zi S/2
a treia zi S-S/4-S/2=4S/4-S/4-2S/4=S/4
S/4=375⇒S=375·4=1500 lei
Verificare: 1500-1500/4-1500/2=1500-375-750=375 lei

Answer 2

prima zi = 1/4 ×x
a doua zi = x/2
a treia zi = 375 lei
x/4+x/2+375 =x
4×x/4+4×x/2+4×375=4×x
x+2x+1500=4x
3x+1500=4x
3x-4x=-1500
-x=-1500
x=1500 lei