9000 ways to create 4-digit passwords using digits from 0 to 9 that the first character can't be 0, but not using the digit 0 as the first character.
We have to see how many different 4-digit passwords we can create by using digits from 0 to 9, such that the first character can't be 0.
Each of the different groups or selections can be formed by taking some or all of a number of objects, irrespective of their arrangments is called a combination.
Here we have 4 selections.
Now let's find the number of options for each of these:
First character = 9 options {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
Second character = 10 options {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
Third character = 10 options {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
Fourth character = 10 options {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
The total number of different combinations is just the product of these 4 numbers:
C = 9×10×10×10 = 9,000
So, we can conclude that the correct option is D.
If you want to learn more about combinations visit here;
brainly.com/question/2280026
