SOLUTION: 1. There are 10 doors to a coliseum. In how many ways can a person go in and out if one can enter any door but leave using another door?

Algebra ->  Permutations -> SOLUTION: 1. There are 10 doors to a coliseum. In how many ways can a person go in and out if one can enter any door but leave using another door?       Log On


   

Question 1191310: 1. There are 10 doors to a coliseum. In how many ways can a person go in and out if one can enter any door but leave using another door?
Answer by ikleyn(52780) About Me  (Show Source):
You can put this solution on YOUR website!
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There are  10*9 = 90  possible different outcomes:

        to enter in any of  10  doors and to leave using any of  9  remaining doors.