Question 863177: Permutation or Combination:
Selecting a president, vice president, and treasurer of the 100-student class.
How do I know if it's permutation or combination?
Answer by jim_thompson5910(35256)   (Show Source):
You can put this solution on YOUR website! Order is important and order matters. Say you had three people and you called them A, B, C. The order ABC is different from BAC because A is president in the first group and B is president in the second group.
So again, order matters. This means we'll be doing a permutation. You could use the nPr formula, but below is a much simpler way.
You have 100 choices for slot 1 (president), 100-1=99 choices for slot 2 (VP), and 100-2 = 98 choices for slot 3 (treasurer). Notice how as you progress through the slots, you lose one person each time. This is because no person can serve multiple posts.
Multiply these choices out: 100*99*98 = 970,200
So there are 970,200 different ways to do this.
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