Question 1150301
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P(20,9) = 20*19*18*17*16*15*14*13*12 = (big number...)<br>
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To the student, who thinks my response is a "fraud"....<br>
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There is not much more that can be added to an explanation.  The manager clearly has 20 choices for the first player in the lineup, then 19 choices for the second, and so on until he has selected 9 players.<br>
It is an elementary problem in permutations....<br>
As for the answer, it is not our objective to work the problem to the end for you.  Our objective is to help you learn HOW to work the problem and get the answer yourself.