A library labels each book with a six-character code to identify the book in its computer system. The first character is either a letter or digit, and this is followed by three digits, then two letters. How many different codes are possible

There are 24336000 different codes that are possible.

Step-by-step explanation:

We know that,

Total alphabets = 26

Total digits = 10

Choices for First place = 26+10=36

Choices for next 3 places = 10 x 10 x 10 = 1000

Choices for last 2 places = 26 x 26 = 676

Total different codes are possible = 36 x 1000 x 676

=24336000

Hence, there are 24336000 different codes that are possible.

answer: 12

step-by-step explanation:

answer: the common difference is -0.10