Consider a Yule process starting with a single individual and suppose that with probability P(s) an individual born at time s will be robust. Compute the distribution of the number of robust individuals born in (0,t).

Emmanuel added 888 links per minute to his chain mail. allesia started 202020 minutes after emmanuel and added 131313 links per minute to her chain mail. how long had emmanuel worked when allesia caught up to him, and how many links had he added?