00:02
How many different ways can a race with five runners be completed? assume that there is no tie.
00:11
Now, this assumption that there is no tie means that no two persons can have the same position.
00:17
So, only one person can come first, one person can come second, one person third, one person fourth, and one person fifth.
00:28
Now, when the race begins, since there are five persons, it means that each one of them has the chance to come first.
00:37
So the first position can be chosen from these five persons.
00:43
Right.
00:44
For the second position, it means that four more persons remain because one already came first.
00:50
So the second position can be chosen from four of these people.
00:56
For the third position, it means that three more persons now have the chance to come a third.
01:02
So for the third position, we'll have three.
01:06
And for the fourth position, it means that three persons already secured a position, the first position, the second position, and the third position.
01:15
So it means that two persons will remain.
01:19
And these two persons have the chance to come fourth...