SOLUTION: A sample of 4 mousetraps taken from a batch of 100 mousetraps is to be inspected. How many different samples could be selected?

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Question 388972: A sample of 4 mousetraps taken from a batch of 100 mousetraps is to be inspected. How many different samples could be selected?
Answer by haileytucki(390) About Me  (Show Source):
You can put this solution on YOUR website!
100C4
Find the number of possible unordered combinations when r items are selected from n available items.
100C4=nCr=(n!)/(r!(n-r)!)
Fill in the known values.
(100!)/(4!(100-4)!)
Cancel out the common factorial factors.
(100*99*98*97)/(4*3*2)
Cancel out the remaining common factors.
25*33*49*97
Multiply 25 by 33 to get 825.
825*49*97
Multiply 825 by 49 to get 40425.
40425*97
Multiply 40425 by 97 to get 3921225.
3921225