Solving Combinations Problem: 7 0s & 3 1s

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SUMMARY

The discussion focuses on calculating the number of sequences consisting of seven 0's and three 1's using combinations. The formula for combinations, represented as C(n, r) = n! / (r!(n-r)!), is confirmed as applicable for this scenario. Participants agree that the total number of sequences can be calculated using C(10, 3), which represents the number of ways to choose three positions for 1's out of ten total positions. The conclusion is that there are 120 unique sequences of seven 0's and three 1's.

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How many sequences are there consisting of seven 0's and three 1's? Example: 0101010000
I was thinking that I could solve this with combinations. However, I am unsure of how to use it in this case. If I remember correctly, the combinations are given by:

[tex]\begin{pmatrix}n \\ r\end{pmatrix}=\frac{n!}{r!\,\left(n-r\right)!}[/tex]

Hmm. Any thoughts on this? Am I on the right track with the above?

Thanks.
 
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There are [itex]2^{10}[/itex] ways of selecting the digits and [itex]_{10}C_3[/itex] ways of having three 1's.
 
Tide said:
There are [itex]2^{10}[/itex] ways of selecting the digits and [itex]_{10}C_3[/itex] ways of having three 1's.
Alright. I was thinking that it didn't matter if they were the same number; I could still use the formula above. Thanks for the confirmation :smile:.
 

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