Question 198486
1) In how many ways can 5 seats on a bench be assigned from amongst 12 people?
If you count arrangements,
there are 12C5 = 792 ways
Each of these sets of people can be arranges in 5! = 30 ways
----
Total # of arrangements = 792*30 = 23760 way
=============================================================== 
2)John and Harry Invited four other people to sit on their bench. In how many ways can these six people be seated on this bench if:
a)there are no restrictions: 6! = 720 ways
-----
b)john is seated at the left end and Harry is seated at the right end
4! = 24 ways
--------------------------
c)John and Harry must be seated together.
5! = 120
------------------------------ 
3)You bought five house numbers at your lumber supply store. The numbers are 1,2,3,4 and 5.
How many three-digit house numbers 
a)are even? 
pick the units digit: 2 ways
pick the 2nd digit: 4 ways
pick the 1st digit: 3 ways
Total # of ways: 2*3*4 = 24
---
b)are possible? 5*4*3 = 60 ways
======================================
Cheers,
Stan H.