Math121: Probabilty Question

If you have 8 balls and 4 are yellow and 4 are red, how many ways can you line them up so that no two yellow or no two red balls are touching?

I only get 2…
ABABABAB
BABABABA

What am I missing??
Apparently, 2 is not the answer.

Hi @livewithnature,

Let me start this reply of mine with a Disclaimer: I haven’t taken Saylor.org Academy’s “MA121: Introduction to Statistics” course yet and I also don’t work at / for Saylor.

Assuming the balls are indistinguishable, I agree with you when you say:

" If you have 8 balls and 4 are yellow and 4 are red, how many ways can you line them up so that no two yellow or no two red balls are touching?

I only get 2…
ABABABAB
BABABABA "

Where exactly, in the MA121 course, did you find this problem? Could you copy and paste the exact text of the question to a new reply in this same discussion thread / topic?

The answer is 4…
ABABABAB
BABABABA
AB
AB
AB
AB
BA
BA
BA
BA