MATH
posted by michele on .
Ten different letters of an alphabet are given .2 of these letter are followed by two digits are used to number the product of a company .in how many ways product can be numbered?
ANS CHOICES ARE
52040
8100
5040
1000
4000

According to the stated question, the conditions are:
The (serial) numbers are produced by two (distinct) letters ("two of these letters") followed by (any) two digits (09), then the number of ways products can be numbered will be:
first letter : 10 ways
second letter: 9 ways
first digit: 10 ways
second digit : 10 ways
Total=10*9*10*10=9000 ways.
If the two digits are to be distinct (which has not been specified), then there are 9 ways for the second digit and the total is 8100.