Question

Mihai a cheltuit o suma de bani in 2 zile . In prima zi a cheltuit 30% din suma , iarba doua zi restul de 35 de lei . Calculati suma de bani cheltuita de Mihai prima zi . Please :/

Answer 1

notam x= suma

x-(30/100*x)-35=0
x-3x/10-35=0 (se amplifica x si 35 cu 10)
10x-3x-350=0
7x-350=0
7x= 350
x= 350/7
x=50

in prima zi: 30/100*50= 15 lei.

Answer 2

Fa așa:
30%=?
70%=35
35:7=5
5×3=15=30%
15 plus 35 =50 lei
100%