Chapter 5.3, Problem 48MS

Here we celebrate the power of algebra as a powerful way of finding unknown quantities by naming them, of expressing infinitely many relationships and connec ions clearly and succinctly, and of uncovering pattern and structure.

Rinky dink links. The local Half-Dollar Store sells cheap key rings (two for a half-dollar) that are easy to link together. You purchase a bunch of rings and use them — three at a time — to create a bunch of Borromean rings as shown in the tri-colored figure in the text (not the all-green figure). When you’re done, you count all the crossings in all your sets of Borromean rings and find the total is 24. How much did you spend on rings at the Half-Dollar Store?