EXAMPLE 3.2.7 SOLUTION
Hint: since we are choosing a subset of 4 people from a set of 10 people, and arranging the four people according to relative strength, the answer can be obtained by computing P(10,4).
 
P(10, 4) = 10 factorial divided by (10 minus 4) factorial
= 10 factorial divided by 6 factorial
= 5,040