Carmen has 6 CDs that she is going to give away. She let her best friend choose 3 of the 6 CDs. How many different groups of 3 CDs are possible?

6C3 = (6*5*4)/(3*2*1) = 20

10

In this problem, we need to find the number of different groups of 3 CDs that can be chosen from the 6 CDs Carmen has. To solve this, we can use the concept of combinations.

The formula for combinations is given by: nCr = n! / (r! * (n - r)!), where n is the total number of objects, and r is the number of objects taken at a time.

In this case, n = 6 (the total number of CDs Carmen has) and r = 3 (the number of CDs to be chosen). Plugging these values into the equation, we have:

6C3 = 6! / (3! * (6 - 3)!)
= 6! / (3! * 3!)

Now, let's calculate each factor step by step:

6! = 6 * 5 * 4 * 3 * 2 * 1 = 720
3! = 3 * 2 * 1 = 6
(6 - 3)! = 3! = 6

Putting everything back into the equation:
6C3 = 720 / (6 * 6)
= 720 / 36
= 20

Therefore, there are 20 different groups of 3 CDs that can be chosen from the 6 CDs Carmen has.