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Olympic Magic

Age 14 to 16
Challenge Level Yellow starYellow star
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The Olympic emblem consists of five coloured rings which overlap to give nine regions. Here is a black and white diagram showing the overlaps:
 
Five interlocking rings forming a W shape - the second overlaps the first, the third overlaps the second and so on. 


In order to contribute to a pension fund for the retiring International Olympic Committee people are asked to deposit money into each region.
The guidelines allow the delegate to take all the money in any one of the rings.

Place the numbers 1, 2, ... 9 in the nine regions so that the amount in each ring is the same. How many different ways can you find to do this?
(Problem from University of Sydney Mathematics Enrichment Groups 1999)

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Label the joints and legs of these graph theory caterpillars so that the vertex sums are all equal.

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The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice.

NRICH is part of the family of activities in the Millennium Mathematics Project.

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