Solve 4-Digit Numbers w/ Same Digit Repeated Twice & Thrice

[Zythyr]

I have no experience in stats and I was wondering if this problem can be solved using stats instead of creating a java program. Can someone please help me.

I am trying to find out how many 4 digits numbers exist that have the same digit repeated in that number twice. And how many 4 digits numbers exist that have the same digit repeated in that number three times.

For example:

5797: The digit 7 appears twice
0410: The digit 0 appears twice

3888: The digit 8 appers three times

So I want to know how many times the digit is repated twice and how many times the digit is reapted three times in the range from 0000-9999.

Can somoene please help me.

 

[EnumaElish]

Yes it can be. This is a combinatorial problem.

how many 4 digits numbers exist = 10C4

same digit repeated twice: you are looking at patterns ddxy, dxdy, dxyd, xddy, xdyd, xydd. How many combinations are possible with each of d, x, y taking on values 1, ..., 10?

 

[Zythyr]

I am not sure how to do solve this problem. I never took Stats.

 

[EnumaElish]

It is a counting problem really.