Question

I know 8C5=56 but I tried using the formula but I dont get 56 for my answer can someone pls explain how to work it out. 10 POINTS​

Answer 1

The combination formula is 8! / (8-5)! * 5!

= 8! / 3! * 5!

= 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1/ 3 * 2 * 1 * 5 * 4 * 3 * 2 * 1 (expand)

= 8 * 7 * 6 / 3 * 2 * 1 (5 * 4 * 3 * 2 * 1 cancels on both sides)

= 8 * 7 = 56 (3 * 2 * 1 = 6)