Question

Serial numbers for a product are to be made using 4 letters followed by 4 digits. the letters are to be taken from the first 9 letters of the alphabet, with no repeats. the digits are to be taken from 0-9 with no repeats. How many serial numbers can be generated?

Answer 1

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:

$n=\frac{9!}{(9-4)!}*\frac{10!}{(10-4)!} \\n=9*8*7*6*10*9*8*7\\n=15,240,960$

There are 15,240,960 ways to generate a serial number.