The Cheapest Bracelet

Strategies and Hints

  1. The most obvious first attempt is:

    open an end link of Chain A and join it to Chain B (5 cents);
    open an end link of the 6-link chain and join it to Chain C (5 cents);
    open an end link of the 9-link chain and join it to Chain D (5 cents);
    open an end link of the 12-link chain and complete the bracelet (5 cents).

  2. The final result (the bracelet) does not have more than two links attached to anyone other link. So, this move would have to be reversed to reach the final solution.

Solution

Open all three links in Chain A and take it apart (6 cents).
Use one of the links to join Chains B and C (3 cents).
Use a second link to join the 7 -link chain to Chain D (3 cents).
Use the third link to turn the 11-link chain into a complete bracelet (3 cents).