Question

If i randomly pick 3 red cards from a deck of card and throw them away, and then give you the deck of card to draw a random card, what is the probability of drawing an ace card knowing that three red cards are missing (but not which cards)?

Answer 1

Since you do not know if one of the red cards is an ACE, then you have to assume there's still at least one left out of the 49 cards.  Four possible ACES in deck, so the probability is 4 out of 49 chance that you'll draw an ACE.