Math Puzzle: How Many Routes Can You Discover?
Attempt to clear up a touring salesman’s directional dilemma
Henry Ernest Dudeney could also be among the many most important puzzle inventors who ever lived. He was born in Mayfield, England, in 1857, the son of a village schoolteacher, and he died in 1930. Dudeney designed brainteasers for newspapers and magazines frequently for many years, and he later compiled most of his puzzles into books. This head-scratcher comes from his 1917 guide Amusements in Arithmetic.
A touring salesman who lives in metropolis A needs to go to all cities from B to P over the course of every week, although not essentially in alphabetical order, and return to A on the finish. He plans to enter every metropolis precisely as soon as. The blue traces are the one roads connecting the 16 cities. The touring salesman might use solely a straight route between any two cities; he isn’t allowed to show on the intersection of two streets. What number of completely different routes are doable?
On supporting science journalism
Should you’re having fun with this text, take into account supporting our award-winning journalism by subscribing. By buying a subscription you’re serving to to make sure the way forward for impactful tales concerning the discoveries and concepts shaping our world in the present day.
If the touring salesman enters a metropolis on one highway, he should depart it once more on one other. To ensure that a spherical journey to be doable in any respect, no less than two roads should result in every metropolis. There are precisely two roads resulting in cities A, B, E, F, G and H. The touring salesman should due to this fact journey on these roads it doesn’t matter what. This additionally determines which roads he’ll use to achieve and depart cities I, J, M and N. The remaining connections are then additionally clear. There’s due to this fact just one doable spherical journey for the touring salesman—AIENHDOFJBMGCKPLA—however he can journey it in two completely different instructions.
Editor’s Word: The model of the puzzle that appeared within the print version of the July/August 2024 problem incorrectly included connections between C and I and between I and M. The error didn’t impression the answer.
