[1] 60 possible ways
There are 5 people with 3 "spots."
We can use the following formula to solve for the possible ways that they could be photographed. This calls for a "permutation."
-> n is the total number of people, 5
-> r is the sample, 3, we are taking a picture of at a time
n! / (n−r)!
5! / (5−3)!
5! / (2)!
120 / 2
60
[2] 10 different groups
There are 5 people with 3 "spots."
We can use the following formula to solve for the possible combinations your group mates could end up being. This calls for a "combination."
-> n is the total number of people, 5
-> r is the sample, 3, we are taking 3 people to be a part of our group at a time
n! / (r!(n−r)!)
5! / (3!(5−3)!)
5! / (3!(2)!)
5! / (3!(2)!)
120 / 12
10