Răspuns:
[tex]notam \: cu \: x \: nr \: gainilor \\ in \: prima \: zi \: \: \: \: \frac{1}{2} \times x = \frac{x}{2} \\ si \: au \: ramas \: \frac{x}{2} \: \: neprinse \\ a \: doua \: zi \: \: \: \frac{1}{2} \times \frac{x}{2} = \frac{x}{4} \\ x - nr \: gaini \: prinse \: in \: prima \: zi \: - nr \: gaini \: prinse \: in \: a \: doua = \: nr \: gaini \: in \: a \: treia \: zi \\ x - \frac{x}{2} - \frac{x}{4} = 40 \\ aducem \: la \: acelasi \: numitor \: \\ \frac{4x}{4} - \frac{2x}{4} - \frac{x}{4} = \frac{160}{4} \\ x = 160 [/tex]
