Advice needed: Flash vs. Applet

I'm developing a learning website. I like to have very advanced tutorials, and believe that an interactive Applet or Flash application would be best. However, I would like advice from an experienced developer in what the best general strategy would be to keep the application quick on slower computers. In other words, tell me what would be the most efficient programming solution. There will be chemistry/math/physics problems which the user is to complete. The user may use the menu to get help at any point during the problems. The program will tally the score and walk the user through steps as needed. Should I use Flash, Applets, or another technology? Advice is needed. ## Deliverables An advisory email. ## Platform Need 3.0+ compliance in Mozilla, IE, and Opera. I'm willing to make the user download something for the tutorials to work. I'm hoping for a solution that will work in slower computers.