Atotal of 6 family members will appear in a portrait. if 3 of the family members may sit in the front row, how many combinations of family members may sit in the front row?

Basically, it is asking in how many ways can you choose 3 people out of a set of six.

combinations = n! / (r! * (n-r)!)
combinations = 6! / 3! * 3!
combinations = 6 * 5 * 4 / 3!
combinations = 20