1. How many 3-letter arrangements are there of the letters of the word CANADA?
This is actually correct! and the answer in your book is correct!
Splitting it up into three different cases
for 1A is is 4!=24
2A's 3*3=9
(Ex.DAA)
3A's=1
(Ex. AAA)
Thus using the additive principle associated with permutations add all three cases together: $\displaystyle \boxed{24+9+1=34}
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