I'm not clear what you are trying to do. If you want a regular quiz,
Bill's example or some of my own in Chapter 7 Examples:
http://www.loyola.edu/education/PowerfulPowerPoint/
might be what you want, but you seem to be presenting a quiz. You say
you don't want the answer to show up on the slide. Why do you need to
put the answer on the slide at all if it is not going to show up? Or, do
you want to show a question, discuss it is as a class and then have the
right answer show up? This could be done with a simple animation. Just
set the entrance animation effect to something for the answer.
If none of the suggestions here (by Ute, Bill, or me) work for you, maybe
you could describe in more detail what you want to do.
--David
--
David M. Marcovitz
Director of Graduate Programs in Educational Technology
Loyola College in Maryland
Author of _Powerful PowerPoint for Educators_
http://www.loyola.edu/education/PowerfulPowerPoint/