00:01
We have the soton bridge club having 10 members, so we're going to say that the n is 10.
00:07
And in part a, we want to determine how many ways can you select a president, a vice president, and a treasurer from those 10 members.
00:17
So in this case, it's going to be a permutation because order matters.
00:21
There is a difference whether you are selected as president versus vice president or treasurer.
00:26
So in this case, we have 10 people to choose from, and we want to select 3.
00:34
So when we are using the formula for permutations, it's equivalent to n factorial over n minus r factorial.
00:47
So in this case, we'll have 10 factorial over 10 minus 3 factorial, or 10 factorial over 7 factorial, which means we have 10 times 9 times 8 times 7 times 6 times 5 times 4 times 3 times 2 times 1 over 7 times 6 times 5 times 4 times 3 times 2 times 1.
01:27
And we can do some canceling.
01:29
The 7654321 on top, cancel with the 7654321 on the bottom, and when we multiply, we get 720...