MathDB
12 Olympians and 88 humans in a Greek village

Source: (2022 -) 2023 XVI Dürer Math Competition Regional E2

May 25, 2024
algebranumber theory

Problem Statement

In a Greek village of 100100 inhabitants in the beginning there lived 1212 Olympians and 8888 humans, they were the first generation. The Olympians are 100%100\% gods while humans are 0%0\% gods. In each generation they formed 5050 couples and each couple had 22 children, who form the next generation (also consisting of 100100 members). From the second generation onwards, every person’s percentage of godness is the average of the percentages of his/her parents’ percentages. (For example the children of 25%25\% and 12.5%12.5\% gods are 18.75%18.75\% gods.) a) Which is the earliest generation in which it is possible that there are equally many 100%100\% gods as 0% 0\% gods? b) At most how many members of the fifth generation are at least 25% gods?