How many lottery tickets would have to be bought for there to be a >=50% probablility that every single possible combination has been chosen? Or for smaller numbers how many people would you need in a room for there to be a >=50% probability that every day of the year is one or more of these people's birthdays?
If these numbers are too large then how many people/tickets would be needed that there is a >=50% probability that >=50% of the lottery tickets/birthdays have been chosen?
Assume that birthdays and lottery tickets are chosen at random and not bunched, and forget about leap years to keep things slightly simpler.
