I would like to think that I have a basic understanding of Bayes Theorem. However, when trying to apply it to this situation, I am stumped. Let's say there are 100,000 people that have a given problem. I estimate arbitrarily that 75% will take a solution that I can offer and of that 75,000, I am hoping that 40% of them reinvest in a certain product. What is the probability that it may happen?

I can't figure out what would be the normalizing constant. Can anybody suggest anything for me? I would be very grateful.