Question

There are 20 students in the high school glee club. They need to pick four students to serve as

the student representatives for an upcoming trip. How many ways are there to choose the
representatives?

Answer 1

4845

Explanation:

Total number of students : 20

Students to be picked : 4

Does order matter? : No

Use combination formula (see attached)

Answer 2

4845 ways

Explanation:

To solve this problem we use the formula of combinations

`nCr=(n!)/(r!(n-r)!)`

Where n is the total number of students that can be chosen and you choose r from them.

So

`n = 20\\r = 4`

Note that in this case the order in which the 4 students are chosen does not matter.

Then

`20C4=(20!)/(4!(20-4)!)`

`20C4=(20!)/(4!*16!)=4845\ ways`