Henry Ernest Dudeney/Puzzles and Curious Problems/274 - Halfpennies and Tray/Solution

Puzzles and Curious Problems by Henry Ernest Dudeney: $274$

Halfpennies and Tray

What is the greatest number of halfpennies that can be laid flat on a circular tray

(with a small brim to prevent overlapping the edge)

of exactly $9$ inches in diameter, inside measurements?

No halfpenny may rest, however slightly, on another.

Of course, everybody should know that a halfpenny is exactly one inch in diameter.

Solution

The tentative answer given by Dudeney is $64$, which he reports as having been achieved by a certain Dr. G.T. Bennett.

There may be room for further investigation.

Sources

• 1932: Henry Ernest Dudeney: Puzzles and Curious Problems ... (previous) ... (next): Solutions: $274$. -- Halfpennies and Tray