SOLUTION: How many combinations of president and vice president can be made in a class of 21?
Klreddick@AOL.com
Algebra.Com
Question 552395: How many combinations of president and vice president can be made in a class of 21?
Klreddick@AOL.com
Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!
P(n,r) = (n!)/((n-r)!)
P(21,2) = (21!)/((21-2)!)
P(21,2) = (21!)/(19!)
P(21,2) = (21*20*19!)/(19!)
P(21,2) = 21*20
P(21,2) = 420
So there are 420 different ways.
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