SOLUTION: In a history class, Colin and Diana both have a multiple choice quiz. There are 10 questions on the quiz. Each question has five possible answers. What is the probability that Co
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Question 1157631: In a history class, Colin and Diana both have a multiple choice quiz. There are 10 questions on the quiz. Each question has five possible answers. What is the probability that Colin will pass if he guesses an answer to each question? Round answers to the 4th decimal place
Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!
hat
What is a passing score out of ten questions?
The probability of at least 
successes in 
trials where the probability of success on any given trial is 
is given by:
\ =\ \sum_{r\,=\,k}^n\,{{n}\choose{r}}\,p^r\,(1\,-\,p)^{n-r})
Your is 10, and your is 0.2, but you don't know , which is the number that represents a passing score.
So for example, if you have to get six correct to pass, your calculation would be:
\ =\ \sum_{r\,=\,6}^{10}\,{{10}\choose{r}}\,(0.2)^r\,(0.8)^{10-r})
Change if the number to pass is different than six.
John
My calculator said it, I believe it, that settles it
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