00:01
So in 41, we have a deck of cards that is shuffled and then divided into two halves of 26 cards each.
00:08
We select one card at random from the first, realize it's an ace.
00:12
We take that ace out of the first half and then insert it back into the second half.
00:18
So now we have 27 cards in the second half and we shuffle it again and we want to compute the probability that the drone card from the second half is an ace.
00:27
So we've got to think about it.
00:28
There's 27 total cards.
00:30
We know for sure that one of those 27 cards is an ace.
00:34
So the probability of one of those 27 cards being an ace is one or 100%.
00:40
With the remaining 26 cards, there could be zero aces, but there could be three aces or somewhere in between.
00:46
We don't really know...