The inspector of a
certain system of tube railways
inspects regularly the company's seventeen lines connecting twelve
stations, as shown on the big poster plan that he is
He wants to arrange
his route so that it shall
take him over all the lines with as little travelling as
He may begin where he likes and end where he likes.
What is his
If the stations are a mile apart, he will have to travel more
than seventeen miles to inspect every line.
How far is he compelled to travel, and which route do you recommend?