SOLUTION: how many ways 20 students can sit in a class of 30 chairs ?

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Question 844068: how many ways 20 students can sit in a class of 30 chairs ?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

Note: various possibilities

how many ways 20 students can sit in a class of 30 chairs? 

Chairs in row: %2830C10%29%2820%21%29

10 empty chairs:  ways of choosing these: 30C10





Chairs in a circle: %2830C10%29%2819%21%29

ways of arranging 20 students is 19!



Chairs random:  30C20