Question 715167: Jeanie is a bit forgetful, and if she doesn't make a "to do" list, the probability that she forgets something she is supposed to do is .5. Tomorrow she intends to run three errands, and she fails to write them on her list.
(a) What is the probability that Jeanie forgets all three errands?
What assumptions did you make to calculate this probability?
Events are .
(b) What is the probability that Jeanie remembers at least one of the three errands?
(c) What is the probability that Jeanie remembers the first errand but not the second or third?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Jeanie is a bit forgetful, and if she doesn't make a "to do" list, the probability that she forgets something she is supposed to do is .5. Tomorrow she intends to run three errands, and she fails to write them on her list.
(a) What is the probability that Jeanie forgets all three errands?
Ans: P(x = 0) = 0.5^3 = 0.125
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What assumptions did you make to calculate this probability?
Events are independent
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(b) What is the probability that Jeanie remembers at least one of the three errands?
P(1<= x <=3) = 1 - P(x = 0) = 1 - 0.125 = 0.875
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(c) What is the probability that Jeanie remembers the first errand but not the second or third?
P(yes,no,no) = (0.5)(0.5)(0.5) = 0.125
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Cheers,
Stan H.
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