SOLUTION: A college professor prepares an exam of only eight questions. Prior to the exam, he gave to students twenty study questions, from which he selected eight to include on the exam. If
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Question 637540: A college professor prepares an exam of only eight questions. Prior to the exam, he gave to students twenty study questions, from which he selected eight to include on the exam. If a particular student knows the answer to only fourteen of the twenty questions, the probability that he will get all eight correct on the exam is approximately
a. 0.0288
b. 0.0552
c. 0.0037
d.0.0238
I'm really stuck on this one!
Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!
The probability that the student will know the first question is 
. Now, since one question is no longer being considered, the probability of the student knowing the second question is 
. The probability of the third: 
. See the pattern? Find the probabilities for all 8 questions, and then multiply all 8 probabilities.
John
My calculator said it, I believe it, that settles it
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