[Slim Pickens]

A train leaves Santa Fe traveling east at 68 miles per hour. One hour later, the train that left Amarillo traveling west at 61 miles per hour is twice as far from the train leaving Santa Fe as the Santa Fe train is from Denver. How far is Denver from Amarillo assuming the planar angle between the lines connecting Amarillo and Santa Fe, and Santa Fe and Denver is pi/7. You may assume shperical geometry applies to the Earth's surface to simplify.

The point is I'll leave your question as an excercise for the reader.