Notam cu s suma initiala
[tex]\bf \dfrac{3}{7}\:\: din \: bani\:\: inseamna:\: \boxed{\bf \dfrac{3}{7}\cdot s }[/tex] suma cheltuita
[tex]\bf s- \dfrac{3s}{7} = \dfrac{7s-3s}{7}=\boxed{\bf\dfrac{4s}{7}}[/tex] cat a mai ramas din suma initiala (restul)
[tex]\bf \dfrac{4s}{7} = 16[/tex]
[tex]\bf 4s = 16\cdot 7[/tex]
[tex]\bf 4s = 112\:\:\:|:4[/tex]
[tex]\boxed{\bf s = 28 \: lei}[/tex]
Raspuns: 28 lei a avut initial
