Henry Ernest Dudeney/Puzzles and Curious Problems/287 - The Handcuffed Prisoners

Puzzles and Curious Problems by Henry Ernest Dudeney: $287$

The Handcuffed Prisoners

Nine dangerous convicts needed to be guarded.

Every day except Sunday they were taken out for exercise, handcuffed together in groups of three, as in the diagram:

On no day in any one week were the same two men to be handcuffed together.

If will be seen how they were sent out on Monday.

Can you arrange the nine men in triplets for the remaining $5$ days?

It will be seen that No. $1$ cannot be handcuffed to No. $2$ again, but $1$ and $3$ can subsequently be so.

Also see

• Fifteen Schoolgirls Puzzle, of which this is a relative

Sources

• 1932: Henry Ernest Dudeney: Puzzles and Curious Problems ... (previous) ... (next): Combination and Group Problems: $287$. -- The Handcuffed Prisoners
• 1968: Henry Ernest Dudeney: 536 Puzzles & Curious Problems ... (previous) ... (next): Combinatorial & Topological Problems: Miscellaneous Combinatorial Puzzles: $464$. The Handcuffed Prisoners