Answer:
Step-by-step explanation:
We have to make 5 place serial number with first two as alphabets and last three as digits.
The alphabets are bonded to first 6 ( A, B, C, D, E, F) where as digits are 10 (say 1 to 10).
Let the serial number be S1 S2 S3 S4 S5.
For Alphabets
For S1 we have 6 alphabets.
Now for S2 we are left with 5 alphabets since there is no repetition one alphabet will be fix for S1.
So the possible combination for S1 S2= 6x5=30.
For Digits
We did the same as we did for alphabets, for S3 we have 10 possibilities, and for S4 and S5 9 and 8 respectively due to the no repetition condition.
So the possible combinations for S3 S4 S5 = 10x9x8=720
So the total number of serial numbers are 30+720=750.