Question

There are 15 students in a social studies class. Two students will be selected to present their term projects today. In how many different orders can two students be selected?

Answer 1

Given:
15 students
2 students must be chosen.
No repetition, no order

This is a combinations problem. We use this formula: n! / (n-r)!(r!)

n = 15 ; r = 2

15! / (15-2)!(r!) ⇒ 15! / 13! * 2! = 105