Riddle: You find yourself in a room that is suspended in the air. The room is 50 feet deep, 50 feet wide and 50 feet tall. The ground is 100 feet below the floor of the room. There is a small doorway on one wall that has a hook at the bottom of it. Two ropes are suspended from the ceiling in the center of the room, a foot apart from each other. You are skilled at climbing ropes. You have a knife in your pocket and you know how to tie any kind of knot. You will not survive a fall of greater than 10 feet from where your hands are holding on. How do you get down to the ground?
Answer: Climb up one of the ropes. Using your knife, cut 45 feet of the other rope off and hold on to it. Tie the remaining 5 feet of rope still hanging from the ceiling into a loop. Tie end of the rope that you cut down to the end of the rope you climbed and feed the lengthened rope through the loop you created. Move over so that you are hanging from the loop instead of the long rope and cut the long rope as high up as you can reach. Transfer your weight so that you are holding onto the long rope with both hands--one on either side of where it is fed through the loop, and slide down to the floor. Then pull your long rope down. You now have a 95 foot rope that you can tie to the hook on the door to climb down to the ground.