(related to Problem: Inspecting A Mine)

Starting from $A,$ the inspector need only travel $36$ furlongs if he takes the following route: $A$ to $B,$ $G,$ $H,$ $C, D,$ $I, H,$ $M, N,$ $I, J,$ $O, N,$ $S, R,$ $M, L,$ $G, F,$ $K, L,$ $Q, R,$ $S, T,$ $O, J,$ $E, D,$ $C, B,$ $A, F,$ $K, P, Q.$ He thus passes between $A$ and $B$ twice, between $C$ and $D$ twice, between $F$ and $K$ twice, between $J$ and $O$ twice, and between $R$ and $S$ twice — five repetitions. Therefore $31$ passages plus $5$ repeated equal $36$ furlongs. The little pitfall in this puzzle lies in the fact that we start from an even node. Otherwise, we need only travel $35$ furlongs.

Thank you to the contributors under CC BY-SA 4.0!



Project Gutenberg

  1. Dudeney, H. E.: "Amusements in Mathematics", The Authors' Club, 1917

This eBook is for the use of anyone anywhere in the United States and most other parts of the world at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this edition or online at If you are not located in the United States, you'll have to check the laws of the country where you are located before using this ebook.