Question

89 POINTS! Please hurry within 2 minutes. Jered's parents are going to repaint their house. They need to select two colors to complete the job. If they previously narrowed their decision down to six colors, how many combinations of two can they choose from?

Answer 1

6 x 5 x 4 x 3 x 2 x 1 = 720

4 x 3 x 2 x 1 = 24

24 x 2 = 48

720 / 24 = 30

Answer 2

The formula for combinations is n! / (r!(n-r)!)

where n is the total number of objects and r is the sample.

So you get 6! / (2!(6-2)!)

The ! means you multiply the number by all numbers below it

so 6! = 6 * 5 *4 * 3 *2 *1 = 720

2! = 2*1 = 2

6-2 = 4, 4! = 4 * 3 *2 *1 = 24

Now you have 720 / 2 * 24 =

720 / 48

Answer = 15 possible combinations.