Răspuns:
3x/7 - a cheltuit in prima zi
⁷⁾x-3x/7=(7x-3x)/7=4x/7 rest
4x/7·1/4=x/7 a cheltuit a2a zi
3x/7+x/7+⁷⁾120=⁷⁾x
3x+x+840=7x
840=7x-4x
x=840:3
x=280 lei suma initiala
[tex]\it \dfrac{3}{4}(1-\dfrac{3}{7})s=120 \Rightarrow\dfrac{3}{\not4}\cdot\dfrac{\not4}{7}s=120 \Rightarrow \dfrac{3}{7}s=120 \Rightarrow s=120\cdot\dfrac{7}{3}=40\cdot7=280[/tex]
