THE LADDER CONUNDRUM

Lots of info in this one. A yacht is in a harbour, with a rope ladder hanging over the side. The water just covers the bottom rung of the ladder. The rungs are 1/4 metre apart, and there are 24 of them. It is low tide, and time is now 1100 hours. The tide now rises at 500 cm every 30 minutes for the next three hours. At the end of this time, how many rungs are covered?

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Scroll down for the answer

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One. Boats float, you know!

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