Assuming that your own ticket is already secured.
From the 5 friends you can only choose 3.
The order in which these friends are chosen is not relevant. So this is a Combination problem.
Where the order is relevant the problem becomes a Permutation problem!
So the answer is 5 combination 3. = ⁵C₃
⁵C₃ = (5 * 4 * 3) / ( 3 * 2 * 1) = 10
You can take 10 groups of any 3 of your 5 friends.
