# Join six five-link chains to form a circular chain

Join six five-link chains to form a circular chain.
To join two chains, you must cut, and then re-weld, a link.

The final number of links in the circular chain will be 30.

What is the minimum number of links you must cut and re-weld to complete the circle/chain?

• Think of each of the five-link chains as a line of hoops or rings that are connected end to end. Mar 23 '16 at 17:59
• I'm pretty sure I've seen this before... (Also, logic-puzzle should only be used for puzzles about logical deduction.)
– Deusovi
Mar 23 '16 at 18:19
• (Not entirely sure if topology applies here.)
– Deusovi
Mar 23 '16 at 18:20
• @Deusovi Topology seems like a ... not-unreasonable tag to me? Mar 23 '16 at 18:20
• @OliveStemforn Click the green checkmark beside the answer that you said solved it correctly. Mar 23 '16 at 20:07

5 Links. Cut one of the segments into separate links,(5 cuts) and use them between each of the 5 remaining segments to form a circle (5 welds)

Edit: The question was changed to stipulate that the chain should become a circle of 30 links in length. While this "solution" is a circle with 30 links, it is only 10 links long and is no longer valid after the update.

As is usual with these puzzles, I'm not sure if this is allowed:

Cut both ends of the first chain
Line up one side of the links of the other 5 chains
Weld the broken link through all 5 whole links.
repeat for the other side
You should now have a "circle" of 10 links around, that has a fat one side (5 chains thick!)
This means that the answer is 2 cuts. See Images.