Wrong, But Useful: Episode 8

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In this month's Wrong, But Useful, @icecolbeveridge (Colin Beveridge in real life) and @reflectivemaths (Dave Gale when he's at home)...

The new puzzle, courtesy of @sherriburroughs:

Dave is, recklessly, walking across a railway bridge1 and is three-eights of the way across when - disaster! He hears a train coming. It's the kind of train that travels at a constant speed of 100 km/h.
If he runs towards the train, he gets off of the bridge just in time; if he runs away from the train, he also gets off the bridge just in time.
How fast does he run?

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Colin

Colin is a Weymouth maths tutor, author of several Maths For Dummies books and A-level maths guides. He started Flying Colours Maths in 2008. He lives with an espresso pot and nothing to prove.

  1. In discussing the problem, I flippantly and incorrectly say "maybe the bridge is a mile long" - there is no information about the length of the bridge. []

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Where do you teach?

I teach in my home in Abbotsbury Road, Weymouth.

It's a 15-minute walk from Weymouth station, and it's on bus routes 3, 8 and X53. On-road parking is available nearby.

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