Jackie C. answered 10/14/20
I am a College Undergraduate who can help with your school work.
Because the order of who gets which prize matters, we will use permutation. We are choosing 3 winners out of 15 runners, so: nPr = n! / (n-r)!
15 P 3 = 15! / 12! = 2730
If you have a TI 83/84 calculator, you can enter "15", hit "MATH", go to "PRB" tab by using the arrow keys, go to nPr, then enter "3".