Two cards are drawn without replacement from an ordinary deck of 52 playing cards. What is the
probability that the second card is a spade if the first card was not a spade?
3 answers
since all of the spades are still there, but one other card is gone, the prob that the next draw is a spade is 13/51
The first card was drawn from 52 cards, giving you a probability of 1/52 cards. One for the one that was selected (it's the only one of its kind in the deck) out of 52 possible cards = 1/52. It was not put back, but remember - it wasn't a spade so all 13 spades are still in the deck, but the deck now only contains 53 cards. Now, the probability that you can draw a spade is 13 out of 53 cards, or 13/53.
Correction - I meant 13/51 cards.