Question

I have tried this problem several times and cannot figure it out!

Four friends order a shirt from a catalogue. There are 14 colors of shirts, 7 are cotton and 7 are blend. each one orders a color at random (there are no repeats) what is the possibility that the friends order only cotton shirts?

Answer 1

well, i'll try :)

you have four friends and each of them chose one shirt.
so without restriction it will be 14C4

picking only cotton shirts will be 7C4

so the probability will be \(\sf \large \frac{ _{7}C_{4} }{ _{14}C_{4}}\)

I'm not sure though, are you doing combinations or permutations?