PuzzlOR: A long walk

John Toczek

Walking in large cities poses some risk to pedestrians. There are poorly designed intersections, mistimed lights and commuters in cars that are anxious to get to their destination.

My new commute to work includes a one-mile walk, which is represented in the accompanying map. Each line represents a segment of that walk, and the line color represents the level of risk for that segment. Red indicates a high risk section, orange indicates a medium risk section, and green represents a low risk section.

Move from circle to circle in any direction you like from start to finish while trying to minimize the total risk. To calculate the total risk of the walk, add up points for all segments as follows: green = 0 points, orange = 1 point, red = 2 points.

A one-mile walking commute

Danger ahead: A one-mile walking commute.


What are the minimum total risk points that can be achieved for the walk?

Send your answer to puzzlor@gmail.com by Aug. 15. The winner, chosen randomly from correct answers, will receive a $25 Amazon Gift Card. Past questions and answers can be found at puzzlor.com.

John Toczek is the senior manager of analytics at NRG in Philadelphia. He earned his BSc. in Chemical Engineering at Drexel University (1996) and his MSc. In operations research from Virginia Commonwealth University (2005).