So, a post over at Mrs. Reilly’s blog (http://mrsreillyblog.wordpress.com/2013/07/30/first-days/) this morning has me thinking about the locker problem again. I am trying to imagine a semi-elegant solution to this follow up question. “So, after all 1000 students have gone through and done their thing, how many total times was a locker door touched?”
I am curious as to whether my students will try to keep track from the point of view of adding how many times each door gets touched or by adding up the number of times that each student touches a door. I’m thinking tables and thinking that the greatest integer function will need to be invoked. Don’t have a clear idea myself yet, and I am certainly open to any suggestions.
(Possible spoiler)
mrdardy, I used your hint about the greatest integer function and would up with this: https://www.desmos.com/calculator/zdjcay1uup
Did I interpret the question (total locker touches) correctly? If so, does that function do the trick?
This looks fantastic – it’s too late for me right now to really dig into this (I should have done so earlier) but I will definitely attend to this solution in the morning. Thanks SO much for sharing.
Michael
Does DESMOS derive this equation, or do you suggest it to the program? I love the table of values attack to see what happens and where the increased # of touches comes from.
Thanks!