Question: A high school has this ritual on the last day of school: The Students go into the hall and stand by their closed lockers. At the first blow of a whistle, the students open every locker. At the second whistle, the students close every second locker (lockers 2,4,6, etc., are slammed shut). At the … Continue reading Locker

A boat

Question: You are in a boat in the exact center of a perfectly circular lake. There is a goblin on the shore of the lake. The goblin wants to do bad things to you. The goblin can't swim and doesn't have a boat. Provided you can make it to the shore — and the goblin … Continue reading A boat