# Two trains and a fly



## robert@fm (Sep 15, 2018)

At the stroke of noon, one train sets off from London and another from Manchester (assume that the separation is exactly 200 miles), both travelling at exactly 100mph, and travelling towards each other. At the moment they depart, an ultra-fit fly takes off from the front of the London train, flying at 150mph. When it lands on the front of the Manchester train, it immediately takes off again and heads back again; and so the performance repeats.

Unfortunately the trains are on a collision course, and end up squashing the fly between them (and not doing the trains or their drivers much good either). How far did the fly travel?

For a bonus point: Which train is nearest to London when they collide?


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## Hepato-pancreato (Sep 16, 2018)

150miles. London to Manchester train nearest to London..


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## mikeyB (Sep 16, 2018)

I’ve just posted this problem on the old hole drilled through the sphere thread.  Did somebody give you a Marin Gardener book for your birthday?


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## Eddy Edson (Sep 16, 2018)

Fondly remember Gardener's column in Scientific American back in the olden days.

I guess the trains will collide in 1 hour, the fly will have travelled 150 miles, and the trains will both be 100 miles from London?


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## C&E Guy (Sep 20, 2018)

There was a guy who went for an interview for a job as a railway signalman.

He was asked, "If two trains are speeding towards each other on the same line, what would you do?"

"Change the signals to red," he replied.

"If that doesn't work?"

"Change the points to divert one train."

"And if that doesn't work?"

"Go and get my brother," he answered.

"Go and get your brother? Why?"

"Because he's never seen a train crash before!"


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