Question 703062: Guessing on an exam. In a multiple choice exam, there are 5 questions and 4 choices
for each question (a, b, c, d). Nancy has not studied for the exam at all and decides to randomly
guess the answers. What is the probability that:
(a) the first question she gets right is the 5th question?
I have so far, n=5 and p=.25. The "5th question" throws me off...
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Guessing on an exam. In a multiple choice exam, there are 5 questions and 4 choices
for each question (a, b, c, d). Nancy has not studied for the exam at all and decides to randomly
guess the answers. What is the probability that:
(a) the first question she gets right is the 5th question?
I have so far, n=5 and p=.25. The "5th question" throws me off...
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If the 5th is the first correct the answer pattern is wwwwc
where w is "wrong" and c is "correct".
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P(wwwwc) = (3/4)^4*(1/4) = 81/1024
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Cheers,
Stan H.
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