My brain is stuck on this question:
At one of the University's Open Days there are 3 first year, 3 second year and 4 third year maths
students who have agreed to help on the day.
How many different ways can they arrive at the common room in the morning for their briefing from
the Open Day organiser
(a) assuming they all arrive at random?
(b) if the first person to enter the room is a first year student, and the last person to enter the
room is a third year student?
(c) if all of the third year students arrive in sequence, one after another?