Question 472796

(i) Calculate the number of possible arrangements of 5 letters chosen from the 8.

number of arrangements = 8P5 = 8!/3! = 6720


Calculate the number of these arrangements
(ii) in which A is placed first,
number of arrangements = 7P4 = 7!/3! = 840


(iii) which contain A. 
number of ways to select another 4 letters (excluding A) = 7C4 = 35

number of ways to arrange these 5 ( including A) = 5! = 120

total possible arrangement that contains A  = 120*35 = 4200


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