THE CLOTHES LINE PUZZLE.
(
Patchwork Puzzles)
A boy tied a clothes line from the top of each of two poles to the base
of the other. He then proposed to his father the following question. As
one pole was exactly seven feet above the ground and the other exactly
five feet, what was the height from the ground where the two cords
crossed one another?
Answer:
Multiply together, and also add together, the heights of the two poles
and divide one result by the other. That is, if the two heights are a
and b respectively, then ab/(a + b) will give the height of the
intersection. In the particular case of our puzzle, the intersection was
therefore 2 ft. 11 in. from the ground. The distance that the poles are
apart does not affect the answer. The reader who may have imagined that
this was an accidental omission will perhaps be interested in
discovering the reason why the distance between the poles may be
ignored.
