BTGmoderatorDC wrote: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?
A. 20
B. 40
C. 216
D. 720
E. 729
OA A
Source: Magoosh
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 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)
Answer: A
Cheers,
Brent
