Question

if there are 20 students in a 5th grade class. Four of these students will be selected to be patrols. In how many ways can the four patrols be selected?

Answer 1

There are 4845 ways to select four patrols

Explanation:

Total number of students in 5 th grade = 20

No. of students selected for patrols = 4

We are supposed to find In how many ways can the four patrols be selected

We will use combination

Formula :
`^nC_r=(n!)/(r!(n-r)!)`

Substitute n = 20 and r = 4

So,the four patrols can be selected in no. of ways =
`(20!)/(4!(20-4)!)=4845`

Hence There are 4845 ways to select four patrols