Answer:
3,628,800 (aka "10!")
Step-by-step explanation:
The first letter in the code can be 10 possible letters.
Since every letter can only be used once, the second letter can only be 9 possible letters.
E.G.: If the first letter is A, the second letter is B-J.
The third letter would be 8 possible letters, than the fourth would be 7, etc.
In math form, figuring out the possible combinations would be written out as so:
10 × 9 × 8 × 7 × 6 × 5 × 4 × 3 × 2 × 1
An easier way to write this out would be using "10!", which stands for "10 Factorial"
The result of the above equals 3,628,800.
