Question 40371: Two trains 150 miles apart are traveling toward each other along the same track. The first train goes 60 miles per hour; the second train rushes along at 90 mile 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 truns around again. It goes on flying back and forth between the two trains until they collide. If the fly;s speed is 120 miles per hour, how far will it travel?
Answer by rajagopalan(174)   (Show Source):
You can put this solution on YOUR website!
A beautiful problem..
If you put this on dynamic programming a computer will go crazy..for 30 minutes..
A common sense solution is possible in just one minute..
Now the trains approach velocity is 90+60 = 150 mph
Distance between traing at start = 150 miles
so Time from start to collision = 150/150 = 1 hour
The fly keeps flying at 120 mph for one full hour.
(Ignore time taken by the fly to turn 180 degrees)
Hence ..how far will it travel? ...= 120 miles .. Maths is easy..Is n't it?
good luck..
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