Question 1157465
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The number of all possible permutations of 4 persons is 4! = 4*3*2*1 = 24.


The number of all possible arrangements, where A an B occupy the end seats is 2*2 = 4

(two positions for A abd B;  and two positions for C and D).


Therefore, the probability is  P = {{{4/24}}} = {{{1/6}}}.
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Solved.