2020 BMT Discrete Tiebreaker #2
Source:
March 10, 2024
combinatorics
Problem Statement
On a certain planet, the alien inhabitants are born without any arms, legs, or noses. Every year, on their birthday, each alien randomly grows either an arm, a leg, or a nose, with equal probability for each. After its sixth birthday, the probability that an alien will have at least arms, at least legs, and at least nose on the day is , where and are relatively prime positive integers. Compute .