Answer:
840 unique ways
Explanation:
There are 8 letters in the word COOKBOOK.
O is repeated 4 times.
K is repeated twice.
To find how many unique ways the word can be rearranged, we'll need to divide 8! by 4! and 2!;
[tex]\frac{8!}{4!2!}=\frac{40320}{24\ast2}=\frac{40320}{48}=840[/tex]