IBM Research | Ponder This | July 1999 challenges
Skip to main content

Ponder This

July 1999

<<June July August>>


Ponder This Challenge:

While bowling, you notice that the ten pins (arranged in a triangle) are labeled with the different integers 0,1,...,9, and that if two pins are side-by-side, the sum of their labels (reduced modulo 10) is equal to the label of the pin in front and between them. For example:             1    2    4    5                3    6    9                  9    5                     4

Add the labels of the two pins in the second row to obtain the label of the one pin in the first row: (9+5=14 = 4 mod 10). But in the example some of the pins have the same label; in the solution, they don't.

While you are busy noticing this, your opponent makes a strike.

How are the pins labeled?


We will post the names of those who submit a correct, original solution! If you don't want your name posted then please include such a statement in your submission!

We invite visitors to our website to submit an elegant solution. Send your submission to the ponder@il.ibm.com.

If you have any problems you think we might enjoy, please send them in. All replies should be sent to: ponder@il.ibm.com

  

Challenge: 07/01/99 @ 12:00 AM EST
Solution: 08/01/99 @ 12:00 AM EST
List Updated: 08/01/99 @ 12:00 AM EST

People who answered correctly:


Attention: If your name is posted here and you wish it removed please send email to the ponder@il.ibm.com.