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Question
Answer the following:
Find the number of words that can be formed by using all the letters in the word REMAIN If these words are written in dictionary order, what will be the 40th word?
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Solution
There are 6 letters A, E, I, M, N, R
Number of words starting with A = 5!
Number of words starting with E = 5!
Number of words starting with I = 5!
Number of words starting with M = 5!
Number of words starting with N = 5!
Number of words starting with R = 5!
Total number of words = 6 × 5! = 720
Number of words starting with AE = 4! = 24
Number of words starting with AIE = 3! = 6
Number of words starting with AIM = 3! = 6
Number of words starting with AINE = 2!
Total words = 24 + 6 + 6 + 2 = 38
39th word is AINMER
40th word is AINMRE
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