]fie x suma initiala
ptr caiete a cheltuit [tex] \frac{x}{2} -1[/tex]
i-a ramas [tex] \frac{x}{2} +1[/tex]
ptr carte a cheltuit [tex] \frac{1}{3} ( \frac{x}{2}+1 )+5= \frac{x}{6}+ \frac{16}{3} [/tex]
i-a ramas [tex] \frac{x}{2}+1- \frac{x}{6}- \frac{16}{3} = \frac{2x}{6} - \frac{26}{6}=29 \\ 2x=29\cdot 6+26 \\ 2x= 200 \\ x=100[/tex]