The people living on the island of Gibberish use the standard Kobish alphabet ( letters, A through T). Each word in their language is 4 letters or less, and for some reason, they insist that all words contain the letter A at least once. How many words are possible?
+26367 The people living on the island of Gibberish use the standard Kobish alphabet ( letters, A through T).
Each word in their language is 4 letters or less, and for some reason,
they insist that all words contain the letter A at least once.
How many words are possible?
\(\begin{array}{|lr|} \hline \text{words with $1$ letter : } &1 \\ \text{words with $2$ letters: } &39 \\ \text{words with $3$ letters: } &1141 \\ \text{words with $4$ letters: } &29679\\ \hline \text{sum: } & 30860 \\ \hline \end{array} \)
