SOLUTION: a true false test has 5 questions what is the probability of getting atleast 4 right by guessing all the answers

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Question 667012: a true false test has 5 questions what is the probability of getting atleast 4 right by guessing all the answers
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!

The probability of successes in trials where is the probability of success on any given trial is given by:



Where is the number of combinations of things taken at a time and is calculated by

You want the probability of getting either 4 or 5, so calculate the probability of getting all 5 right:



then calculate the probability of getting exactly 4 right:



And then add the two values. Note: , , anything to the zero power is 1, and anything to the 1 power is itself.

John

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