Where a large number of workmen are employed on a
building it is customary to provide every man with a little disc
bearing his number.
These are hung on a board by the men as they
arrive, and serve as a check on punctuality.
Now, I once noticed a
foreman remove a number of these checks from his board and place them
on a split-ring which he carried in his pocket.
This at once gave me
the idea for a good puzzle. In fact, I will confide to my readers that
this is just how ideas for puzzles arise.
You cannot really create an
idea: it happens—and you have to be on the alert to seize it
when it does so happen.
It will be seen from the illustration that there
are ten of these checks on a ring, numbered 1 to 9 and 0.
The puzzle is
to divide them into three groups without taking any off the ring, so
that the first group multiplied by the second makes the third group.
For example, we can divide them into the three groups, 2—8 9
7—1 5 4 6 3, by bringing the 6 and the 3 round to the 4, but
unfortunately the first two when multiplied together do not make the
Can you separate them correctly? Of course you may have as many
of the checks as you like in any group.
The puzzle calls for some
ingenuity, unless you have the luck to hit on the answer by chance.