Normal: it is very close to 50/50. It does still lean, but only just. It's close enough that in practice any guess is fine. Binomial: it is 50/50. The reason

Normal: it is very close to 50/50. It does still lean, but only just. It's close enough that in practice any guess is fine. Binomial: it is 50/50. The reason these change the situation dramatically is that under normal or binomial, you are waaaay more likely to be in a situation that is close to 50/50 to begin with because they are way more likely to occur. The quirk of this question is that a 0 green 100 red urn is just as likely as a 50-50 red/green urn using a uniform distribution - hence if you get red on the first draw you are much more likely to be in a heavily tilted red urn.