## Thinking Mathematically (6th Edition)

The number of possible permutations if r items are taken from n items is nPr =$\frac{n!}{r!(n-r)!}$ The number of ways that people can select their favorite joke told by a woman and their three favorite jokes told by a man is: = 2C1 x 4C3 =$\frac{2!}{1!(2-1)!}$ x $\frac{4!}{3!(4-3)!}$ = 2! x $\frac{4!}{3!1!}$ =2*1 x $\frac{4*3!}{3!1!}$ =2 x 4 =8 ways