Question

How many three digits codes can be formed using 0 to 9 if the last digit cannot be 0 or 1 repetition of digits is allowed

Answer 1

There are 10 ways to choose the first digit.
10 ways to choose the second digit.
8 ways to choose the third digit.

So 10x10x8 ways.

Answer 2

the only problem i have is whether a number like 003 is considered as three digit number. If it is, then 10x10x8 ways.

It not, then the first digit must be from 1 to 9
9 x 10 x 8 ways

Answer 3

It is asking about "codes" so I assume leading zeros are allowed.