Little Suzy has a tricycle (you know, with three wheels). She wants to travel 1 mile with the tricycle, but she wants to spare her tyres (you know the price on tricycle tyres just keep going up). She is taking 2 spare tyres.

Assume she knows when to exchange wheels so that each of them travels an equal distance. How far does each wheel travel at the end of one mile? How did she exchange the wheels?

The total distance travelled is one mile per each of three tire locations for a total of 3 tire/miles.  With five tires, each would travel 3/5 miles.  The easiest way to do this is to go 2/5 miles.  Replace two wheels.  Go 1/5 mile.  Change the only original tire left (it's through) with one that was taken off first.  Go 1/5 mile and change that tire with other originally removed tire.  1/5 more and you are there.

 

Posted by Charles Phipps on 2004-02-26 00:56:34