I sat down to read a story about a problem returning a cellphone and over the course of this entertaining post I was reminded of a mathematical challenge that I faced whenever I had to layout rows of light fixtures, or supports for runs of conduit. I didn’t have a name for it then, but I do now: Fencepost Error.
A tip of the hat goes to Mr. Propp for skillfully combining mathematics and consumer warranty information—vital lessons for us all.
Customer: “But this receipt proves that I bought the phone less than two weeks ago!”
Manager: “I understand, sir. But you can only get a full refund if you return it within fourteen days, and you’re one day late.”
This surreal exchange isn’t from The Twilight Zone. It took place, with me starring as the hapless Customer, in a perfectly ordinary suburb called Watertown, Massachusetts, and this insidious mixture of social and mathematical ills could visit your town too. The social sickness is a familiar one: big companies like Verizon Wireless can screw you over any way they like, and if they screw over enough people in enough different ways, then the people who got screwed over in any particular way will be too dispersed to find one another and take action. The mathematical malaise? Fencepost error.
Cartoon by Ben Orlin (https://mathwithbaddrawings.com/). Follow him on Twitter @benorlin.
View original post 6,307 more words