GeekDad Puzzle of the Week: Gear Up

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Image: Flickr/Avrene

I hope this is a fairly kid-friendly, hands-on challenge — perhaps even with the opportunity for a teachable moment or two. That said, if you don’t happen to have Lego gears lying around the house, feel free to illustrate, animate, or just explain your answer. The puzzle is this: combine the standard Lego gears of 8, 12, 16, 20, 24, 36 and 40 teeth in a functional gear train so that one rotation of an initial gear with 36 teeth results in 20 rotations of the final axle. You needn’t use all gears, but you can for style points. Accomplishing this with exactly five axles is worth two contest entries. (Hint: you may want to consider loading more than one gear onto each axle.)

Submit your answer by this Friday to GeekDad Central for your chance at this week’s $50 ThinkGeek gift certificate!

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