vittovangind wrote:
Brent,
Many thanks for your feedback. My issue still is that I'm having a hard time reformulating the question as you did.
Cheers,
Vitto
Fair enough.
Here's a similar solution that utilizes the Fundamental Counting Principle (perhaps a more familiar approach).
Take the task of seating handing out shirts and break it into stages.
Aside: When breaking a task into stages, you should ask yourself "How would I accomplish this task?" Here's one such way:
Stage 1: hand out the 3 green shirts
So, we must 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)
Stage 2: hand out the 3 red shirts
Now that we have given green shirts to 3 of the 6 children, the remaining 3 children MUST receive the red shirts.
So, there's only
1 way to hand out the red shirts.
By the Fundamental Counting Principle (FCP), we can complete the two stages (and thus hand out the 6 shirts) in
(20)(1) ways ([spoiler]= 20 ways = A[/spoiler])
Cheers,
Brent
Aside: For more information about the FCP, watch our free video:
https://www.gmatprepnow.com/module/gmat-counting?id=775
