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Red Card Blue Card

Age 11 to 14 Short Challenge Level:

Sally has 5 red cards, numbered 1, 2, 3, 4 and 5, and 4 blue cards, numbered 3, 4, 5 and 6.

She wants to line them up so that the colours alternate, and so that the number on each red card is a factor of every number next to it.

How can she do this?


This problem is adapted from the World Mathematics Championships
You can find more short problems, arranged by curriculum topic, in our short problems collection.