SOLUTION: There are 1000 students in the senior class at a certain high school. The high school offers two Advanced Placement math / stat classes to seniors only: AP Calculus and AP Statist

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Question 821699: There are 1000 students in the senior class at a certain high school. The high school offers two Advanced Placement math / stat classes to seniors only: AP Calculus and AP Statistics. The roster of the Calculus class shows 95 people; the roster of the Statistics class shows 86 people. There are 43 overachieving seniors on both rosters.
12. What is the probability that a randomly selected senior is in at least one of the two classes?
(10 pts)

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13. If the student is in the Calculus class, what is the probability the student is also in the Statistics
class? (10 pts)

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
There are 1000 students in the senior class at a certain high school. The high school offers two Advanced Placement math / stat classes to seniors only: AP Calculus and AP Statistics. The roster of the Calculus class shows 95 people; the roster of the Statistics class shows 86 people. There are 43 overachieving seniors on both rosters.
12. What is the probability that a randomly selected senior is in at least one of the two classes?
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P(calc or stat) = [95+86-43]/1000 = 0.138
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13. If the student is in the Calculus class, what is the probability the student is also in the Statistics
P(stat | calc) = P(stat AND calc)/P(calc) = (43/1000)/(95/100) = 43/95
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Cheers,
Stan H.
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