Question

Tatiana is a counselor at summer camp. She wants to take 20 campers on a hike and wants to choose a pair of students to lead the way. In how many ways can Tatiana choose this pair of children?

Answer 1

There are 190 ways to choose this pair of children

Explanation:

Total number of students at summer camp = 20

Tatiana wants to choose a pair of students to lead the way

Number of students in a pair = 2

We are supposed to find In how many ways can Tatiana choose this pair of children

So, We will use combination

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

n = 20

r= 2

So,
`^nC_r=(n!)/(r!(n-r)!)=(20!)/(2!(20-2)!)=190`

Hence There are 190 ways to choose this pair of children