salmon in a mountain river must overpass two waterfalls
Source: Polish MO Finals 1974 p2
August 23, 2024
probabilitycombinatorics
Problem Statement
A salmon in a mountain river must overpass two waterfalls. In every minute, the probability of the salmon to overpass the first waterfall is , and the probability to overpass the second waterfall is . These two events are assumed to be independent. Compute the probability that the salmon did not overpass the first waterfall in minutes, assuming that it did not overpass both waterfalls in that time.