Question 196915: Hi.
I have my final in Finite math on Thursday and my teacher gave us a
Study give were he includes some probability problems. The bad news is that we didn’t cover probability during the semester. He told us that the problems were going to be extra credit since we didn’t cover this section. Please I need help. I really need those extra credit points, and I am lost.
Here are some of the problems:
1. A die is rolled 5 times. Find the probability that:
a) exactly 2 threes are thrown
b) No more than 2 fives are thrown
c) Between 1 and 4 are thrown
2. A Box Contains 5 White (W) and 4 Black (B) marbles. 3 marbles are drawn without replacement. Find the following:
a) P (2 W / 1st B)
b) P (At least 1W / 1st B)
d) P (W / 1St and 2Nd B), but this time, assume replacement.
2. Assume 8 distinctly title books: 2 green, 3 brown, 1 red, 1 blue, and 1 yellow.
a) Looking only at titles, how many ways can these 8 books be arranged on a shelf?
b) Looking only at titles, how many ways can 5 of 8 books be arranged on a shelf?
c) Looking only at color, how many ways can these 8 books be arrange on a shelf?
d) Looking only at titles, how many ways can we choose 5 books to read?
e) How many ways can we choose 2 brown books to read?
f) Looking only at color, what is the probability that we choose 2 green books to read?
These are only some of the questions but everything else just revolved around the same topic.
Thank you,
Fred
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! 1. A die is rolled 5 times. Find the probability that:
a) exactly 2 threes are thrown
# of ways to select two places from the five: 5C2 = (5*4)/(1*2) = 10
P(getting a 3) = 1/6
P(not getting a 3) = 5/6
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P(2 threes if a die is tossed 5 times) = 10(1/6)^2(5/6)^3 = 0.1608
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b) No more than 2 fives are thrown
P(0,1, or 2 5's in 5 throws) = 0.9645
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c) Between 1 and 4 are thrown
P(1,2,3 or 4 in 5 throws) = 0.5980
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2. A Box Contains 5 White (W) and 4 Black (B) marbles.
3 marbles are drawn without replacement.
Find the following:
a) P (2 W / 1st B) = [5C2*4C1]/[9C3] = 0.4762
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b) P (At least 1W / 1st B)
What do you mean by "1st B"?
Is this supposed to be a conditional statement?
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d) P (W / 1St and 2Nd B), but this time, assume replacement.
That's confusing.
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2. Assume 8 distinctly title books: 2 green, 3 brown, 1 red, 1 blue, and 1 yellow.
a) Looking only at titles, how many ways can these 8 books be arranged on a shelf?
Ans 8! = 40320
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b) Looking only at titles, how many ways can 5 of 8 books be arranged on a shelf?
Ans: 8P5 = 6720
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c) Looking only at color, how many ways can these 8 books be arrange on a shelf?
Ans: 5! = 120
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d) Looking only at titles, how many ways can we choose 5 books to read?
Ans: 8C5 = 56
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e) How many ways can we choose 2 brown books to read?
Ans: 3C2 = 3
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f) Looking only at color, what is the probability that we choose 2 green books to read?
Ans: 2C2/8C2 = 1/28
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Cheers,
Stan H.
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