Henry Ernest Dudeney/Puzzles and Curious Problems/343 - Tom Tiddler's Ground/Solution

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Puzzles and Curious Problems by Henry Ernest Dudeney: $343$

Tom Tiddler's Ground
I am on Tom Tiddler's ground picking up gold and silver.
Here we have a piece of land marked off with $36$ circular plots,
on each of which is deposited a bag containing as many sovereigns as the figures indicate in the diagram.
Dudeney-Puzzles-and-Curious-Problems-343.png
I am allowed to pick up as many bags of gold as I like,
provided I do not take two lying on the same line.
What is the greatest amount of money I can secure?


Solution

$47$ sovereigns.


Proof

These are contained in $10$ bags, all deposited on the outside plots, thus:

$4$, $5$ and $6$ in the first row
$5$ in the second row
$4$ in the third row
$3$ in the fourth row
$5$ in the fifth row
$5$, $6$ and $4$ in the bottom row.

Total: $47$.


If you include $5$ bags containing $6$ sovereigns each, you can get only $9$ bags and so a value of $46$ sovereigns.

$\blacksquare$


Sources