Permutations &Combinations in Probability

8 people of different heights are to be seated in a row. what is the probability that (a) there are at least 3 people sitting between the tallest and shortest? (b) the tallest and shortest are sitting next to each other?

Hi, if you could please explain how to do the problem above I would really appreciate it! Stats is my weak point in math and I would really appreciate if you could explain the logic behind the work you did, if not its okay! Thanks anyway!