3 ms·
To your edit, yes, and there would certainly still be a lot of collisions.
by asow92 4y ago
To your edit, yes, and there would certainly still be a lot of collisions.
- travisjungroth 4y agoMy second answer is a lower bound on the correct answer and extremely close to correct. Think of finding the ID collision first. The probability of having at least one ID collision where they also share the same birthday is pr(2 matching ids) * pr(birthday match in 2 people) + pr(3 matching ids) * pr(birthday match in 3 people)... The probability of having 3 matching IDs is extremely low. Assume you already have a match of size 2. Now you're looking for 1/10^19 match with ~1/10^10 draws. Not good odds. So we can ignore everything after the ID match of size 2, and get very close with 96% * 1/365 or 0.26%.