Phone-in quiz TV

I have briefly watched such a thing and I became curious as to how they arrive at the solution. I am on about the quiz which has only one answer which tend to be numeric. These things seem impossible. I think they have a right to publish not just the answer but also the step-by-step process in arriving at the answer. This should clearly send a message to the people phoning in that they have next to no chance of getting the right answer. I think at the moment, they are debating about publishing the odds of getting the answer. This may not be adequate because how would you accurately calculate the odds?