How Fast Does the Dog Run in This Intriguing Math Puzzle?

[Asiadeep]

"Yes, when I take my dog for a walk," said a mathematical friend, "he frequently supplies me with some interesting puzzle to solve. One day, for example, he waited, as I left the door, to see which way I should go, and when I started he raced along to the end of the road, immediately returning to me; again racing to the end of the road and again returning. He did this four times in all, at a uniform speed, and then ran at my side the remaining distance, which according to my paces measured 27 yards. I afterwards measured the distance from my door to the end of the road and found it to be 625 feet. Now, if I walk 4 miles per hour, what is the speed of my dog when racing to and fro?"

- An interesting puzzle for you guys to figure out.

 

[neutrino]

The only thing puzzling about this is what does it have to do with quantum physics?

 

[RandallB]

Unless it might help unify Particle Physics with GR astrophysics - -
If not, we should stick with Lee Smolin and other quantum gravity ideas, and maybe someone can move this to the General - Brain Teasers forum.

 

[Mentz114]

Boring. I first saw this puzzle 25 years ago. Easy to solve using LQG.