Question

How many three digit numbers are there in which all digits are same?


Please answer

Answer 1

Step-by-step explanation:

The third digit can be any digit (10 possibilities) but cannot be equal to the first two digits. Therefore, there are (10-2) 8 possibilities for the 3rd digit. So there are 9 * 9 * 8 = 648 possibilities

Answer 2

The first digit cannot be 0, so there are 9 options for the first digit.

the second digit can be any number (10 possibilities) but cannot be equal to the first digit. Therefore, there are (10-1) 9 possibilities for the 2nd digit.

The third digit can be any digit (10 possibilities) but cannot be equal to the first two digits. Therefore, there are (10-2) 8 possibilities for the 3rd digit.

So there are 9 * 9 * 8 = 648 possibilities.