Three people, named Adam, Beth, and Carl, are standing in a straight line, facing forward. Carl can see both Adam and Beth, Beth can see only Adam, and Adam cannot see anyone. There’s a pile of 5 hats in a cupboard – three blue hats and two red hats. Adam, Beth and Carl are each…
Peter and Maggie are an old married couple, and over the course of their years they’ve found it does them good to take it in turns to lie. Maggie lies on weekdays with ‘n’ in them while Peter lies on days with ‘r’. On which days could they both claim to have lied the day…
It’s another coin riddle! You are given a standard balance scale and 12 coins that look identical, but one of them is counterfeit and weighs either more or less than the others (you don’t know which). You have writing materials but nothing else. What is the minimum number of times you need to weigh the…
This one is only loosely defined as a “brainteaser.” In fact, it’s often used as an interview question to test a candidate’s approach to problem-solving. It’s thought that Microsoft was the first employer to use this interview brainteaser. The question is simple: What makes manholes round? Ponder it and come up with as many answers…
A great mathematician was once asked to come up with a riddle. She sat in thought for a while before finally she said the following: “Not a single soul isn’t unable to understand that nobody doesn’t like the fact that nobody doesn’t love nobody who isn’t nobody. But what is the name of nobody who…
I make objects for which the buyers have no use. I build homes for those who have no need of housing. My trade goes back thousands of years and will likely continue for thousands more, for as long as there are people there will be those in need of my services. What is my job?
