Calculate Your Age, the Hard Way

Browsing around in my blog links, I found this:

Your Age By Diner & Restaurant Math

Try it for yourself, and then:

• Can you explain how it works?
  You will have to use a little algebra. If you were at my pre-algebra workshop, this will be like the “Choose a number” problem.

• Can you explain why this puzzle will not work next year?
  What would you change to make it work in some year other than 2007?

• Can you make up a problem like this?
  Or can your students?

And if you get stumped, the answer is here.