stolyar
take places? how many places are there? three as usual? or 25?
There are total 25 people. I assume that all the chances should be considered equal.
25!/5!*20!
Am I right? Am I wrong? Or am I just dreaming?
Your answer equals about 53000....does that even make sense for arranging five people? I took this to mean that if _ _ _ _ _ are the five places, the combinations could be:
1 _ _ _ _ or
_ 5 _ _ _ or
_ 3_ 4 1
Where the blanks represent places taken by people NOT on the five person team, but of some of the other 20.
SO...
If only one member places, it could be:
1 _ _ _ _ or
_ 1 _ _ _ or
_ _ 1 _ _ or
_ _ _ 1 _ or
_ _ _ _ 1
Now multiply this by 5 to get all 5 members = 25 combs.
OK, so if two members place, we have more...
1 2 _ _ _
1 _ 2 _ _
1 _ _ 2 _
1 _ _ _ 2
_ 1 2 _ _
_ 1 _ 2 _
_ 1 _ _ 2
_ _ 1 2 _
_ _ 1 _ 2
_ _ _ 1 2
So there are ten here, but we have to multiply this by 5 * 4 to cover all members. So that equals 200.
Now for three we alse have 10 combs (5C3) but we multiply this by 5 * 4 * 3 to get 10 * 60 = 600
For four we get 5C4 = 5 * 5*4*3*2 = 600
for five we get 5! = 120
So lets add these up (my answer has obviously changed)
25 + 200 + 600 + 600 + 120 = 1545
Comments?