Can some one explain to me how to do it? And what the correct answer was?
A box contains 3 spade cards and 7 diamond cads are chosen at random.
a.What is the probability that 2 diamond cards are chosen?
b.If 3 cards are drawn, what is the probability that is 1 spade cards?
c.What is the probability that three cards are drawn without replacement in the order of diamond, spade, and diamond?
2007-06-12 07:38:57 · 3 answers · asked by Sky C 1 in Science & Mathematics ➔ Mathematics
a. 7/10*6/9 = 47%
b. 3(0.7*0.7*0.3) = 44%
c. 7/10*3/9*6/8 = 17.5%
I determined b by doing a quick probability tree. Of eight possible outcomes, only three result in exactly one spade (0.7*0.7*0.3)
2007-06-12 07:45:43 · answer #1 · answered by gebobs 6 · 0⤊ 0⤋
a) There are 10 cards, 7 of which are diamonds. So picking a diamond first has a probability of 7/10, which leaves a pile of 9 cards left with 6 diamonds, so the probability of getting a diamond on the second draw is 6/9 = 1/3. So the total probability is (7/10)(1/3) = 7/30.
b) "is 1 spade cards"? Do you mean the probabiltiy that one and only one of the cards is a spade, or at LEAST one?
c) Use the same reasoning used in part a), then mutiply the three probabilities together.
2007-06-12 14:48:59 · answer #2 · answered by Anonymous · 0⤊ 1⤋
a) 7 C 2 / 10 C 2
b) exactly ONE? (7C2)(3C1) / (10 C 3)
c) 7/10 * 3/9 * 6/8
2007-06-12 14:43:52 · answer #3 · answered by Pat B 3 · 0⤊ 0⤋