A tribe named Mumbo-Jumbo has $3$ letters in their alphabet, how many words are there with length no greater than $4$? I answered $3^4+3^3+3^2+3^1$. The author's answer is $40$, did the author add up $3^3+3^2+3^1+3^0$ by accident?

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    $\begingroup$ Your answer is fine. The book is wrong. $\endgroup$ Oct 11, 2018 at 21:45
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    $\begingroup$ Well, I suppose you could call the empty word a word if you want to. But there are $3^4=81$ words of length exactly $4$ and they certainly count. $\endgroup$
    – lulu
    Oct 11, 2018 at 21:45
  • $\begingroup$ There 40 possible words to jumbo of lenght less than 4 including the sound of silence minus all the tongue tieing jumboes that don't mumbo. $\endgroup$ Oct 12, 2018 at 3:02


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