This is why I’m no good at maths . . .

15 12 2007

Because problems such as the following, taken from Daniel Dennett’s Darwin’s Dangerous Idea (p. 134), just do my head in:

There is a famous story about the mathematician and physicist (and coinventor of the computer) John von Neumann, who was legendary for his lightning capacity to do prodigious calculations in his head. (Like most famous stories, this one has many versions, of which I choose the one that best makes the point I am pursuing.) One day a colleague approached him with a puzzle that had two paths to solution, a laborious, complicated calculation and an elegant, Aha!-type solution. This colleague had a theory: in such a case, mathematicians work out the laborious solution while the (lazier, but smarter) physicists pause and find the quick and easy solution. Which solution would von Neumann find? You know the sort of puzzle: Two trains, 100 miles apart, are approaching each other on the same track, one going 30 miles per hour, the other going 20 miles per hour. A bird flying 120 miles per hour starts at train A (when they are 100 miles apart), flies to train B, turns around and flies back to the approaching train A, and so forth, until the trains collide. How far has the bird flown when the collision occurs? “[Read the solution below the fold],” Von Neumann answered almost instantly. “Darn,” replied his colleague, “I predicted you’d do it the hard way.” “Ay!” von Neumann cried in embarrassment, smiting his forehead. “There’s an easy way!” (Hint: how long till the trains collide?)

The solution is two hundred and forty miles. And why it is so is an absolute bloody mystery!

P.S. Figuring out the time it took for the trains to collide was simple enough, or so I believed when I tackled the problem during my spare time at work. Factoring in the bird was another matter entirely.

Advertisements

Actions

Information

8 responses

15 12 2007
Sean the Blogonaut

I hate maths, almost as much as I hate religion 🙂

15 12 2007
AV

I was never disciplined enough at school to tackle the more difficult subjects like Calculus. It’s something I regret now. But I did rather enjoy the above puzzle, nonetheless.

16 12 2007
stephen

The great philosophical theologian Eric Mascall is reputed to havce said that, those people who studied Philosophy at University were not bright enough to do matehmatics.
I did Maths at Adelaide Uni in the early 70s, what was called Ye Olde Maths, I found that when I was released on unsuspecting students some years later my niece who was then in Year 8 was doing the Field Theory we had done in 2nd Year Uni. …that was New Maths!
Used to be able to differentiate and integrate with the best of them…but I certanly can’t now!

16 12 2007
Bruce

They make it half way (50k total) at an hour, so at two hours they collide. Two times 120 is 240.

16 12 2007
Bruce

D’oh. K? I mean miles.

16 12 2007
AV

They make it half way (50k total) at an hour, so at two hours they collide. Two times 120 is 240.

Yes, but how many times did the bird fly back and forth between the trains?

16 12 2007
AV

(P.S.: any further stupid questions I ask will simply serve to demonstrate what I have asserted in the title of this post.)

17 12 2007
Simmo

The left side of my brain has gone numb, I cannot do this shit.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s




%d bloggers like this: