Question: How many n-digit binary (0,1) sequences contain exactly k 1s?
Could someone explain to me why the answer is n choose k? I don't understand it.
Have you stopped to think about this?
There is a string of n symbols, either a zero or a one.
So you have k places to put a one. So choose k from n.
Put zeros everywhere else.
Have you stopped to think about this?
There is a string of n symbols, either a zero or a one.
So you have k places to put a one. So choose k from n.
Put zeros everywhere else.
Thanks for your explanation. I did think about it, but I've been having a hard time understanding the n choose k concept. So, if I understand this correctly...
"n choose k" is simply the number of possible ways to choose k items from a total of n?