500
Imagine a ship in the middle of the ocean. The ship has a rope ladder that hangs over the side so that its bottom step just touches the top of the water. Each step of the ladder is five inches away from the step above it and from the step below it. How many steps will be underwater when the tide has risen by 10 inches?
What is 0. (As the ship rises the ladder will rise with it. The bottom step will still just touch the water.)