I guess those Wall Street writers at Business Insider think about more than just money:
Business Insider is headquartered in a city that also has a number of bridges, and so we were curious as to whether a tour of the bridges of New York City, going over each bridge exactly once, was possible.Why does anyone care?
This particular puzzle is, at a glance, mostly just a fun observation, whose only application is for particularly fastidious marathon runners. However, it holds an important place in the history of mathematics. Euler's writings on the Bridges of Koenigsburg problem represented some of the first work in what would become the modern mathematical areas of topology and graph theory...So yeah, pretty cool stuff.
Graph theory is enormously useful in studying networks. Power grids, computer networks, and relationships between people on social networking sites — to give just a few examples — can all be modeled by different types of graphs, and results from graph theory are essential to understanding and managing these complex systems.