Question

Mihai a cheltuit o suma de bani in doua zile.In prima zi Mihai a cheltuit 30% din suma,iar in a doua zi restul de 35lei.Calculati suma de bani cheltuita de Mihai in prima zi

Cum se face?

Answer 1

x=suma totala

x=30%x +35

x=(30/100)x +35

x=(3/10)x +35, inmultim cu 10

10x=3x+350

7x=350

x=50

50*30%=50*(30/100)=15 lei

Answer 2

Fie x suma de bani
Prima zi: 30/100*x=3x/10
A doua zi: 35 lei 
x=35+3x/10
10x=350+3x/-3x
7x=350/:7
x=50 lei
Prima zi: 3*50/10=15 lei