Today’s puzzle: How many animals do I have if all but 3 are dogs, all but 3 are cats, all but 3 are pigs and all but 3 are cows?
Last week’s puzzle was getting U2 onto the stage in 17 minutes. The key insight is to realize that you have to get the two slowest people (Adam and Larry) to cross together, otherwise you haven’t a chance since the 10+5 minutes they use up separately doesn’t leave enough remaining time. But you can’t have them go first since there won’t be anyone to bring the flashlight back. Here’s the solution: Bono and Edge cross (2 minutes) and Bono returns (1 minute). Adam and Larry cross (10 minutes). Edge returns (2 minutes). Bono and Edge cross (2 minutes). Total 17 minutes.