I drive at an average speed of 30 miles per hour to the railroad station each morning and just catch my train. On a particular morning there was a lot of traffic and at the halfway point I found I had averaged only 15 miles per hour. How fast must I drive for the rest of the way to catch my train?

Tricky Maths Problem

The train is just about to leave the station and there is no way I will be able to catch it this time.

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