Henry Ernest Dudeney/Modern Puzzles/44 - Find the Distance

Modern Puzzles by Henry Ernest Dudeney: $44$

A man named Jones set out to walk from $A$ to $B$,

and on the road he met his friend Kenward, $10$ miles from $A$, who had left $B$ at exactly the same time.

Jones executed his commission at $B$ and, without delay, set out on his return journey,

while Kenward as promptly returned from $A$ to $B$.

They met $12$ miles from $B$.

Of course, each walked at a uniform rate throughout.

Now, how far is $A$ from $B$?

I will show the reader a simple rule by which the distance may be found by anyone in a few seconds without the use of a pencil.

In fact, it is quite absurdly easy -- when you know how to do it.

1926: Henry Ernest Dudeney: Modern Puzzles ... (previous) ... (next): Arithmetical and Algebraical Problems: Locomotion and Speed Puzzles: $44$. -- Find the Distance
1968: Henry Ernest Dudeney: 536 Puzzles & Curious Problems ... (previous) ... (next): Arithmetical and Algebraical Problems: Speed & Distance Puzzles: $72$. Find the Distance