Question 481554: A student is asked to answer 9 out of 13 questions on an exam, In how many ways can she select the questions to be answered?
Answer by Alan3354(69443)   (Show Source):
You can put this solution on YOUR website! A student is asked to answer 9 out of 13 questions on an exam, In how many ways can she select the questions to be answered?
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Her 1st choice is 1 of 13, then 1 of 12, 11, etc
--> 13*12*11...*6*5
= 13!/4!
= 259,459,200 ways
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But, the order is irrelevant. IE, if she choose question #6 as her 2nd, or as her 7th, it makes no difference.
So the big number is divided by 9!
= 259,459,200/9!
= 715 ways
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