SOLUTION: Consider strings of length 9 with elements being a, b or c. How many strings will contain at least 6 b’s?

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Question 534218: Consider strings of length 9 with elements being a, b or c. How many
strings will contain at least 6 b’s?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Consider strings of length 9 with elements being a, b or c. How many
strings will contain at least 6 b’s?
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# of strings with at least 6 b's = 9C6*2^3 + 9C7*2^2 + 9C8*3 + 9C9
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= 84*8 + 36*4 + 27 + 1
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= 844
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Cheers,
Stan H.