I need help with this question: How many bit strings of length 15 have exactly three 0s?
[Math] How many bit strings of length 15 have exactly three 0s
discrete mathematicseducationrecreational-mathematics
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Best Answer
There are 15 ways to put the first zero, fourteen (since one spot already has a zero) ways to put the second zero, and thirteen ways to put the third zero.
The zeroes all look the same, so you then have to divide by the number of ways the three could be ordered (which is 3! for the 3 zeroes, or 6)
So, the number of ways to do it is 15*14*13/6