00:01
In this problem, it is said that the access code to a house's security system consists of six digits.
00:06
We need to determine how many different codes are available if each digit cannot be repeated.
00:12
So the access code has six digits, so one, two, three, four, five, and six.
00:19
Now, consider the first digit.
00:22
Now, this can be any one of the ten digits from zero to nine.
00:26
So that means that there are ten different options to choose from when selecting the first digit.
00:31
Now consider the second digit.
00:34
It is said that each digit cannot be repeated.
00:36
And because of that, this second digit will be any one of the 10 digits except for the digit which we already selected for the first place...