Math Help - How many bit strings of length 12...?

1. How many bit strings of length 12...?

contain at most ten 1's and at most four 0's?

Im so lost :P

Thanks!

2. Re: How many bit strings of length 12...?

Honk. This is what you do. Do case work. With 2 zeros, the number is 12C2, 12C3, 12C4 for the rest. This is so because you are choosing where to place your 0s, and the 1s are determined.

3. Re: How many bit strings of length 12...?

Thanks for answering, but I'm not too sure on what you meant :P

4. Re: How many bit strings of length 12...?

If there are just two zeros, and you know where they are, how many numbers are there? Just one as the other numbers are just one. So, if you pick where those two numbers go, that gives you the number of ways to have just 2 zeros.