Question: In the harbor of a small town, there is a large boat. Coming off of the boat is a ladder reaching down so that the bottom rung is just above the surface of the water. As the tide comes in, the water rises at 1 foot every 30 minutes, and continues like this for 3 hours. If the rungs are each 1 foot apart, how many rungs are under water when the tide stops rising?
Answer: No rungs are under water. The ladder is attached to a boat which rises with the tide, therefore, the bottom rung will stay just above the surface of the water.
Question: Two men, Watson and Holmes, are out in the extremely dry forest. They are completely surrounded by a large forest fire on one side and a dangerous cliff on the other. The wind is blowing the forest fire towards them and the cliff. The fire will reach them in about one day.
Holmes turns to Watson, "I have matches, berries, and enough water for a day. We aren't going to die." How can they avoid getting swallowed up by the forest fire?
Answer: They can start a fire of their own with the matches and the wind will blow that fire in the same direction as the forest fire and they can take refuge in the section of the forest they burn down.