There is a mob of 3000 people, 1 of whom is a zombie while the other 2999 are not.
Every minute, all 3000 people form 1000 groups of three.
If there are any zombies in a group of three, all three end up zombies.
What is the probability that after 5 minutes there will be exactly 100 zombies in the mob?
Please provide up to 5 decimal places as necessary.