How is yellow next to green in the question without a purple?

The rule doesnt say purple and yellow HAVE to be together, it says that IF there is a purple next to a yellow THEN it has a red on either side.

This had me a little confused too but if you put PY in 5 and 6 you HAVE to put R next to them. And since you have to include every color in every 8 beads you now have to put O at 8 and we know in the rules that R & O cannot be next to each other.