A team of 15 soccer players needs to choose a captain and a co-captain. Is this an example of permutations or combination. Then find the number of possiblities.

With permutations we care about the order of the elements, whereas with combinations we don’t. For this question order matters, because you have two different positions you want to fill (captain, and co-captain).

This would be written as 15p2

To find the number of possibilities we want to use the permuation equation.

(,)=!(−)!

P=permutation

n= the set or population (15 soccer players)

r= subset (1 captain and 1 co-captain, total of 2)

(,)=(15,2)

=15!(15−2)!

= 210

If u are confused about !(factorial) in the equation here is a quick explanation

Many calculators have a factorial key (look for the ! symbol). This function of the calculator will automate the multiplications, but if you do not have a calculator that can compute factorials you just have to go like this

1! = 1

2! = 2 x 1 = 2

3! = 3 x 2 x 1 = 6

4! = 4 x 3 x 2 x 1 = 24

5! = 5 x 4 x 3 x 2 x 1 = 120

6! = 6 x 5 x 4 x 3 x 2 x 1 = 720

7! = 7 x 6 x 5 x 4 x 3 x 2 x 1 = 5040

8! = 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 = 40320

9! = 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 = 362880

10! = 10 x 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 = 3628800

etc

Hope this helps!!