Please help me! I understand what the question is asking for, but I can’t seem to get the right answer. The correct no. of ways should be $645,120$, though that may be incorrect. If anyone is kind enough to show me the solution, I would be very grateful.
“$10$ people are to be seated in a row. What is the total number of ways in which this can be done if Eric and Carlos always have exactly one of the other people sitting between them?”
EDIT: Oh wow that was fast! Thank you for your kind hints! I was finally able to get the answer.