This is part of a TopCoder.com algorithm practice question and I cannot wrap my head around it. I am given a lottery format and I need to calculate the odds. One particular format is that the numbers must be in non-descending order. The numbers do not have to be unique, so I can repeat the same number.
Example: The "PICK TWO FROM TEN IN ORDER" game means that the first number cannot be greater than the second number. This eliminates 45 possible tickets, leaving us with 55 valid ones. The odds of winning are 1/55.
How do I calculate this?