I was going through this question on a site. It stated as below,

> 
> One more problem that is tying me up..I think because it is so much
>  simpler than what I have been working on. Any help would be great =)
> 
> 
> What is the probability of getting exactly $6$ heads and $3$ tails in $9$
>  coin tosses of an unbiased coin?
> 
> 
> 

Now I were to solve the problem, I would have made a table of all the **heads** and **tails**. But this problem size is **very big** ($2^9$ is *large*). Is there any other possible way to solve the problem?

Please help me out.

Thanks.