Marinada '21

[lang=hr] Marko ima magični tetraedar na čijim stranama pišu brojevi $1$, $2$, $3$ i $4$. Ako je u nekom bacanju pao broj $3$, u idućem bacanju je vjerojatnost za svaki broj $0.25$. Ako je pao broj $2$, u idućem bacanju mogu pasti samo $2$ ili $4$, oba s vjerojatnošću $0.5$. Marku je u prvom bacanju pao broj $3$ i odlučuje bacati dok ne dobije $1$ ili $4$. Kolika je vjerojatnost da će dobiti $4$? [/lang] [lang=en] Marko has magic tetrahedron with numbers $1$, $2$, $3$ and $4$ written on its sides. If Marko throws $3$, then in the next throw, probability of getting any number is $0.25$. If he throws $2$, in the next throw he can only get $2$ or $4$, each with probability of $0.5$. In the first throw, Marko got $3$, and he keeps throwing until he gets $1$ or $4$. What is the probability that he will get $4$? [/lang]