IOM 2017, Блиц — Задача 80

OLYMPIAD OF METROPOLISES. Moscow, September 4 · 4 септември 2017 г.

Условие

Giray had three 100-lira banknotes and two 50-lira banknotes in his right pocket. In his left pocket, he had four 50-lira banknotes and two 100-lira banknotes. Giray moved a random banknote from the left pocket to the right one, and then moved a random banknote from the right pocket to the left one. After that a random banknote was stolen from his right pocket. How many times is the probability that a 100-lira banknote was stolen greater than the probability that a 50-lira banknote was stolen?

Отговори

Решение

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Оригинал в Архива: blitz.pdf · официални решения: answers-blitz.pdf