Question

3 students are selected from a class of 15 to

attend a seminar. How many different ways can
this choice be made?

Answer 1

455 different ways

Explanation:

3 students are selected from a class of 15 to attend a seminar.There is no matter in order of these students, so you should use combination's formula:

`C^(15)_3\\ \\=(15!)/(3!\cdot (15-3)!)\\ \\=(15!)/(3!\cdot 12!)\\ \\=(12!\cdot 13\cdot 14\cdot 15)/(3!\cdot 12!)\\ \\=(13\cdot 14\cdot 15)/(2\cdot 3)\\ \\=13\cdot 7\cdot 5\\ \\=455`

different ways