# Wrong, But Useful: Episode 8

/podcasts/wbu8.mp3

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

- … completely forget about the Maths Book Club, which was going on during the recording;
- … get all excited about the MathsJam conference on the weekend of November 2nd-3rd
- … suggest mixing up homeworks a bit (based on this article);
- … consider Dave’s determination to practise squaring two-digit numbers until he can’t get them wrong;
- … have their minds boggled by Riemann, quantum and random matrix theory;
- … discuss The Man Who Knew Too Much by David Leavitt;
- … disprove how many teachers there are on twitter;
- … return to the C3 exam and look at @srcav’s take on how it affected his students;
- … play Book Towers and 10;
- … realise it’s hard to prove something geometrical on a podcast;
- … and set a new puzzle.

The new puzzle, courtesy of @sherriburroughs:

Dave is, recklessly, walking across a railway bridge ((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.)) 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?