Respuesta :
Answer:
When choosing the shirts it doesn't matter what order they're chosen in because at the end you'll have the same four shirts ... so it's a combinations question (rather than a permutations question where the order of choice makes a difference)
so number of groups = 6C4 = 15
another way is to evaluate 6P4 / 4! = 360/24 = 15
Explanation:
i smart