In our fast-paced and advertisement-oriented world, it is easy to get trapped. In fact, there are people who specialize in trapping the public.

The invitation comes in the mail. You are invited to visit a new condominium complex at some beach or lake or mountain setting. They'll give you gas money to drive there. They'll give you free lodging and free meals. Why, you even have guaranteed prizes waiting on you, perhaps a new Oldsmobile Cutlass or a color television. Of course, you could also wind up with a cheap transistor radio or a quartz watch instead. All you have to commit to is a 30-minute tour and a short sales pitch. You are free to say "no;" there will be no hard feelings.

How can these companies afford to do this? Well, it's easy. The odds have been figured to the fifth decimal …