Question

(a) How many ways are there to arrange 3 people in a line (order matters) using a group of 5 people?

Answer 1

60.

Explanation:

This is a permutation exercise because order matters. The formula is n!/(n-r)!. In this case n=5 and r=3 so,

5!/(5-3)! = 5!/2! = 5!/2 = (5*4*3*2*1)/2 we can simplify the 2 and obtain 5*4*3= 60.