Lessons 18-19 on Web Assign

Question

Evaluate the expression.

C(10, 8) · C(9, 7)

C(11, 7)

 

Answer 1

C(10,8) * C(9,7)

10! 9! = 10 * 9 * 8! * 9* 8 * 7! 10 * 9 * 9 * 8

____ * -------- --------------------------- = ----------------- = 1620

2! *8! 2! 7! 2! 8! * 2! 7! 2 * 2

C(11,7)

11! = 11 * 10 * 9 * 8 * 7! 11 * 10 * 9 * 8

----- ------------------------ = ------------------ = 330

7! 4! 7! 4! 24