Replying to Ok I need algebra 1 help..

No Im not fucking stupid, I just havent seen this stuff in 6 years and once you learn higher level math you tend to forget the easy shit ha..

Im trying to help this kid out, but I can't even get it so Im coming to you guys so I dont look as stupid as I really am. Heres the two questions that I can't get. The first one I think Im close but I believe Im missing a step, the second question we were never taught so Im not even sure where to start.

10. A group of stockholders are to elect a president, vice-president, secretary and a treasurer from 6 board members who qualify.  How many different ways can the officers be elected?

I think its somewhere close to 360, I just take 6 options for the first office, times 5 for the second, times 4, times 3 to get 360 but this seems to easy, where am I messing up?

11. If U equals the Universal set which is equal to {1,2,3,4,5} and if X = {3,5}, Y = {1,2,3} and Z = {2,3,4}, find the following:
1. X n Z
2. X u (Y n Z)
3. X u Y

Never taught this, and I have no idea how to start..

No Im not asking you to do my homework, since this isnt mine. Kid came to me for math help and I can do all but these two so please help me help him.