# Calculating probability of a random sample without replacement

For this question, assume I have a standard deck of cards (52 cards, 13 of each set).

My question is: if I were to randomly draw 7 cards, how would I calculate the probability of at least one of those cards being a Spade?

Then, supposing no spades were drawn, how do I calculate the probability that the next card I draw is a spade?

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Easiest is to calculate the probability that out of seven cards none of them are spades and take that away from 1. – Bob Durrant Jan 12 '12 at 19:39

For problem 1, it is easier to work out the probability that none are spades. This is $1 - 39/52 * 39/51 * 39/50 .... * 39/46) = .204$