For this flashcard, I’m struggling to understand why you’d have 8! instead of 9! for the second column where we’re trying to find the # of ways Bill and Bob can be paired with 2 other people. Any help?

I think it’s supposed to be 10! of the top of column 2, is that right @Leaderboard ?

It’s 8!. The reason is that we are taking Bob and Bill out of the 10 people. We have 8 people left, and we’re choosing two from that group of 8.

Oh okay, thanks