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Problem: (SAT Subject Test Math Level 2)
Three cards are drawn from an ordinary deck of 52 cards. Each card is replaced in the deck before the next card is drawn. What is the probability that at least one of the cards will be a spade?
Since the drawn cards are replaced, the draws are INDEPENDENT. Independent events are those that have no effect on each other. The probability that none of the cards was a spade = 39/52 x 39/52 x 39/52 = 3/4 x 3/4 x 3/4 = 27/64.
Probability that 1 card was a spade = 1 - 27/64 = 37/64.