Answer:
15,240,960 serial numbers
Step-by-step explanation:
Since no repeats are allowed and the order matters, the number of possible serial numbers is given by the product of the permutation of 4 out of 9 letters by the permutation of 4 out of 10 numbers:

There are 15,240,960 ways to generate a serial number.
Answer:
36,579.5180
Step-by-step explanationan: