Mrs lunette has 18 students in her class. she wants to send 3 of these students to pick up book for the class. how many combinations of 3 students can she choose?

Mrs Lunette can choose 816 combinations of 3 students.

Step-by-step explanation:

We can use the combination formula to find the number of combinations Mrs Lunette has,

Number of combinations =

Where,

is the total number of students.

is how many students can be chosen at a time.

Now we can substitute the values to the above equation,

Number of combinations =

=

=

=

=

=

Mrs Lunette can choose 816 combinations of 3 students.

so, converting firstly the mixed fractions to improper fractions and then "adding".