Marinada '21

[lang=hr] Na šok i nevjericu mladog Artura, čarobnjak Merlin iz svog džepa vadi dvije \textit{začarane kockice}. Ove kockice imaju posebnu moć: vjerojatnost dobivanja broja $1$ na takvoj kockici je dvostruko veća od vjerojatnosti dobivanja broja $2$, vjerojatnost dobivanja broja $2$ je dvostruko veća od vjerojatnosti broja $3$ i tako dalje do broja $6$ (dakle, vjerojatnost dobivanja broja $x$ je dvostruko veća od vjerojatnosti dobivanja $x+1$). \\ Merlin je bacio obje začarane kockice pred Artura. Kolika je vjerojatnost da je zbroj brojeva na tim kockicama $7$? [/lang] [lang=en] To the shock and disbelief of young Arthur, the wizard Merlin takes out two \textit{enchanted dice} from his pocket. These dice have a special power: the probability of landing a $1$ on such die is twice the probability of landing a $2$, the probability of landing a $2$ is twice the probability of landing a $3$, etc. all the way to $6$ (i.e. the probability of landing $x$ on the die is twice the probability of landing $x+1$). \\ Merlin throws both of his enchanted dice in front of Arthur. What is the probability of the sum of numbers landed being $7$? [/lang]