Question 1069296
What they mean is the number of 2-character sequences
made with two different characters,
chosen from a set of 8 different characters.
You have {{{8}}} choices for the first character.
For each of those {{{8}}} choices,
you have {{{7}}} left to choose from for the second character.
The possibilities {{{multiply}}} , don't they?
So, you have {{{7*8=highlight(42)}}} possible sequences.