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How do I solve the following combinations problem?The sociology test has 15 true/false...
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Middle School Teacher
A combination is when there is no repetition and order doesn't matter. The theorem is...
n! / r!(n-r)!
where n is the number of things to choose from (in this case true/false questions) and you choose r of them (in this case the questions that are answered correctly.
n = 15
r = 11
15! / 11!(15-11)!
15! / 11! * 4! = 1365
There are 1365 ways to answer 11 correctly.
Posted by samhouston on August 17, 2011 at 2:41 PM (Answer #1)
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