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If the letters of the word LUCKY are arranged in all possible ways and the words are arranged in a dictionary, then find the rank of the word LUCKY.

 

Option: 1

92


Option: 2

61


Option: 3

93


Option: 4

95


Answers (1)

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Given that the word is LUCKY. 

The lexicographic order of the letters of the given word is C, K, L, U, Y. The words that begin with C will come first in the lexicographic order.

If the letter C is in the first place of the five-letter word, then the remaining four letters can be arranged in 4! ways. On proceeding like this, 

\begin{aligned} & \mathrm{C}(----)=4 ! \text { ways } \\ & \mathrm{K}(----)=4 ! \text { ways } \\ & \mathrm{LC}(---)=3 ! \text { ways } \\ & \mathrm{LK}(---)=3 ! \text { ways } \\ & \mathrm{LUCKY}=0 \text { ! ways } \end{aligned}

So, the rank of the word LUCKY is given by,

\begin{aligned} & =4 !+4 !+3 !+3 !+0 ! \\ & =(4 \times 3 \times 2 \times 1)+(4 \times 3 \times 2 \times 1)+(3 \times 2 \times 1)+(3 \times 2 \times 1)+1 \\ & =24+24+6+6+1 \\ & =61 \end{aligned}

Therefore, the rank of the word LUCKY is  61

Posted by

Ritika Harsh

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