Answer: Permutation Problem
There are 5040 permutations possible
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Explanation:
Order matters because the positions are different.
(A,B,C,D) is different from (B,A,C,D) because the first means person A is the assistant while the second means person B is the assistant.
We have 10 choices for the first slot, 9 for the second, 8 for the third, and 7 for the fourth. We count down the values because a person cannot be reselected to serve multiple positions simultaneously.
Multiply out those values to get 10*9*8*7 = 5040
There are 5040 permutations possible.
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As an alternative, you can use the nPr permutation formula with n = 10 and r = 4 like so
We get the same answer as before.