The answer to the chain problem

The other day I posited a problem regarding linking a chain.

A woman has four pieces of chain.  Each piece is made up of three links.  She wants to join the pieces into a single closed ring of chain.  To open a link costs 2 cents and to close a link costs 3 cents.  She has only 15 cents.  How does she do it?

Most likely you drew it like this?

If so, you are totally normal.  Normal but wrong.

Drawing it like this means you start thinking about how to join the links at FOUR points.  Your brain gets stuck on four... you do the math and you are over the 15 cent limit.  Now perhaps you suspect a trick, so you begin to think about that perhaps you don't have to join them all.  Wrong.  These are all avenues your brain runs down but essentially lead you astray.

Rule number three for getting smarter is to practice and learn to change the representation.  That is, look at things differently.  The easiest way to do this is to draw or model it differently.

So here you go - I've represented it differently.  Think about opening the three bottom links and using them to join the other pieces.

Hope you got this.

To recap:  The ways to get smarter:

• Automatize your thinking as much as possible
• Change the way you represent things
If you follow the link above, I highly recommend you click through to the Hanoi tower.  Like steroids for the brain.