1) Rosala....I believe the value of n is 8
Reasoning
The first letter can be chosen 3 ways...either A, B or C
But....the second letter can only be chosen 2 ways.....for instance....if A is the first letter, the second can only be chosen 2 ways, either another A or C
And notice that each successive letter can only be chosen in 2 ways......for instance...if the second letter is B, the third letter can only be another B or A
So.....we need to solve this to find the number of additional letters, m, after the first one
3 * 2^m = 384 divide by 3
2^m = 128
And m = 7 makes this true
So....the the number of total letters is
First one + m additional = 1 + 7 = 8
Another way to see this is
3 * 2 * 2 * 2 * 2 * 2 * 2 * 2 = 384
