Real Probability

Probability Level 2

Two packs of playing cards (each containing 52 cards) are thoroughly mixed and two cards are taken at random one after the other without replacement. What is the probability that both of them are queens?

9/1339 1/13 1/169 7/1339

Kanishk Singh by Kanishk Singh , 21, India

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2 solutions

The probability that both of them are queens = Probability the first card is queen x Probability the second card is queen
P = 8 104 \frac{8}{104} x 7 103 = 7 1339 \frac{7}{103} = \frac{7}{1339}

1 Helpful 0 Interesting 0 Brilliant 0 Confused
Debtanu Bhuiya
Jun 9, 2014

In this case the second event is dependent on first so P(both are queen)=(8C1x7C1)/(104C1x103C1)=7/1339

1 Helpful 0 Interesting 0 Brilliant 0 Confused

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