six candidates are called for interview to fill four post in an office. assuming that each candidate is fit for each post determine the number of ways which (1) first and second post can be filled . (2) first three post can be filled . (3) all the four post can be filled

Total no. of candidates=6

(i) No. of ways filing first & second posts = no. of permutations of 6 candidates taking 2 at a time

(ii) No. of ways filing first three posts = no. of permutations of 6 candidates taking 3 at a time

(iii) No. of ways filing all the four posts = no. of permutations of 6 candidates taking 4 at a time

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