I guess I'm a bit confused as to what you want to do. It seems to me that
if you are going to have three questions by slide 10, then you should
have a slide (perhaps, slide 11) that includes those three questions.
Then, keep having duplicate slides with more questions. That works and
would be easiest if you know in advance which question go on the overview
slide at which point.

Macros would be useful if you don't know in advance. There are a lot of
ways to do this. I could imagine a button that adds text to an overview
slide that corresponds to a question (if you know the questions in
advance but don't know which ones will be asked). It would use code that
looks something like this:

With ActivePresentation.Slides("Overview").Shapes(2).TextFrame.TextRange
   .Text = .Text & chr$(13) & "What is the cost of production? $4B"
End With

If the questions aren't predetermined, you'll need to ask for the
questions (possibly using an InputBox or a control text box) and the
answers so you can add that to the slide.

--David

I'm presuming that the questions are on your earlier slides and therefore you
know what they are!

How about producing a summary slide with all the questions in seperate text
boxes. Use vba at the start to set .visible to false for all and then have
code on relevant slides to set textboxes individually to .visible=true at
appropriate times. This way everytime you jump to the summary only the "used"
questions will show. Hope that makes sense.