Brain Buster #1

Thursday August 25th 2005, 3:02 pm Printer Friendly Version
Filed under:Miscellany
Posted By: Matt

On my way home I stopped at Grand Central Station (en route from Connecticut to JFK) to have lunch with a college friend. He kindly gave me something to occupy myself on the flight home:

Find a five-digit number which, when multiplied by 4, yields another number with the same five digits in reverse order.

I guess this is pretty easy with a pen and paper, but I didn’t have anything to write with on the plane, so I had to do it in my head. My brain was aching something awful by the time I got the answer.

Update: Comments contain spoilers, so don’t read them if you want to figure it out yourself. I would be interested to know how many people bother to tackle the problem and with what success.


2 Comments »

  1. 21978 x 4 = 87912

    Voila :-)

    Comment by Cedric — 8/25/2005 @ 3:37 pm

  2. No good result here. 13 minutes with paper. Could have been much better, but I tried it first without paper and then with set of equations. Actually writing 2xxx8 on paper was then enough to find the rest.

    Comment by Ondrej Brablc — 4/19/2006 @ 11:38 pm

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