Two trains 100 km apart are traveling toward each other along the same track. The first train goes 50 km per hour; the second tr
ain rushes along at 80 km per hour. A fly is hovering just above the nose of the first train. It buzzes from the first train to the second train, turns around immediately, flies back to the first train, and turns around again. It goes on flying back and forth between the two trains until they collide. If the fly's speed is 120 km per hour, how far will it travel(how much distance it will cover before colliding )?
