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?

Question

Arjun Wang

Mathematics

9 August, 07:38

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?

+3

Answers (1)

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Jessie Hanson · 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