00:01
Okay, if i throw a coin eight times, each coin task could be head or tail.
00:07
So there are two outcomes per throw.
00:11
I do it eight times, just two times two times two, eight times two, eight times.
00:15
So two power eight outcomes are possible, ranging from eight heads all the way down to eight tails.
00:23
And two power eight is two hundred and fifty six.
00:29
That's the first one, two five, six.
00:32
Now, exactly three heads would be head, head, head, tail, tail, tail, tell.
00:42
That's one way of doing it.
00:46
And of course there are more ways than one.
00:49
It could be head, head, head, tail, head, tell, tell.
00:56
Now to work it out, i suppose these letters were all different.
01:00
There would then be eight factorial ways of arranging eight letters that are all different.
01:08
But they're not all different.
01:10
We have repeats.
01:11
We have three heads, so divide by three factorial for the repeats.
01:17
We have five tails, so divide by five factorial for the repeats.
01:24
That's the answer for a number of ways of arranging three heads and five tails...
