Show Slide Layer using Trigger

I am trying to set up  slide where the user has to click 5 out of 10 possible places on a picture to pass. I have invisible boxers around the areas that turn green when they click on that location. I want it to show slide layer correct as soon as they clicked 5 of the 10 places. What trigger can I use so it can be any combination of the 10 possible answers to trigger the correct layer to show. Thank you!