Problem Solving : Permutation and combination Problem 3: If the letter of the word SEQUESTERED are arranged in all possible ways and these words are written out as in a dictionary form, then what is the 50th rank of the word SEQUESTERED is ?
If the letter of the word SEQUESTERED are arranged in all possible ways and these words are written out as in a dictionary form, then what is the 50th rank of the word SEQUESTERED is ? Solution: So the word SEQUESTERED can be arranged in dictionary form of letters as D E E E E Q R S S T U Hence the number of words begin with DEEEEQR = 4! / 2! =12 and the number of words begin with DEEEEQS = 4! =24 the number of words begin with DEEEEQT = 4! / 2! =12 12+24+12 =48 so next word U becomes last word hence next words are 49 and 50 will be DEEEEQURSST is 49th word and DEEEEQURSTS is the 50th word and the answer --> 50th rank of the word SEQUESTERED is " DEEEEQURSTS "