An anthropologist discovers an isolated tribe whose written alphabet contains only six letters called a, b, c, d, e, and f.
The same letters cannot be used twice in the same word. If each different sequence of letters constitutes a different word in the language, what is the maximum number of six-letter words that the language can employ?
since the order of the letters is significant to the words, this is a Permutation problem.
then for the first letter of the six-letter word, ...
This uses permutations to solve a word problem.