Green & Red Shirts

In how many different ways can 3 identical green shirts and 3 identical red shirts be distributed among 6 children such that each child receives a shirt?

Seeking a set up or hints.

 

We can take this question and ask an easier question: In how many ways can we choose 3 of the 6 children to receive a green shirt?

Notice that, once we have given a green shirt to each of those 3 chosen children, the REMAINING 3 children must get red shirts. In other words, once we have given green shirts to 3 children, the children who get red shirts is locked.

So, in how many ways can we select 3 of the 6 children to receive a green shirt?
Since the order of the selected children does not matter, this is a combination question.
We can choose 3 children from 6 children in 6C3 ways (= 20 ways)

 

6C3 = 6!/(6 - 3)!•3!

6C3 = 720/(3!)(3!)

6C3 = 720/36

6C3 = 20 ways

 

correct

 

We will get into probability later on in my self-study, if you're interested..