Go, Spot, Go!

Dick and Jane noticed each other down a long hall. They were 90 meters apart when they started walking towards each other. Dick was walking briskly at the rate of 2 meters per second, and Jane (who was in high heels!) moved along at the rate of 1 meter per second.

Dick's dog, Spot, noticed Jane at the same time Dick did. Spot started running back and forth between the Dick and Jane at the rate of 3 meters per second.

What distance does Spot run before Dick and Jane finally meet?

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