How many ways can a president, vis-president and treasurer be selected from a group of 15 students?

455ways

Step-by-step explanation:

This is expressed as 15 C 3 (C - combination)

The concept of combination is used when we talk about selection.

Now we are selecting 3 from a sample of 15

15 C 3 = 15! / (15-3) ! 3! = 15 * 14*13*12!/12!*3*2

= 5 * 7 * 13 = 455ways