00:01
All right, so we are given a, b, c, d, e, and f, how many words if no repetition is allowed can be made out of those six letters? so we want to make words using the six letters and repetition is not allowed.
00:20
So basically, this is simple, it's just six factorial.
00:23
Because if we have got the words like this one, two, three, four, five, six, so this would be a, b, c, d, e and f.
00:39
So once you fix a at the beginning, okay, all these numbers qualify to fill in the first letter of that word.
00:50
So there will be how many ways of filling it? two, three, four, five, six ways of filling it.
01:00
The second one, since the repetition is not allowed, it will be five, next four, next three, next two, next one.
01:09
And then that gives us seven, six, seven hundred and twenty.
01:19
So it's seven hundred and twenty.
01:23
Let me just seven twenty.
01:29
And it will also want to find.
01:31
Out how many of such words would start and end with a consonant...