SOLUTION: How many ways can a president and vice president be selected in a class of twenty-one students?

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Question 284276: How many ways can a president and vice president be selected in a class of twenty-one students?
Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
nPr=n!/(n-r)! Permutation-order is important.
.
21!/(21-2)!
=21*20*19!/19!
=20*21
=420 ways
.
Ed