One coin on each side of the balance. If they don't balance, one of them is the rogue. In which case, weigh both against another coin to find out which it is.
Puzzle
- Thread starter wings
- Start date
Split coins into 3 groups of 3. Weigh G1 vs G2 and then G1 vs G3.
If G1 heavier/lighter than both G2 and G3 then rogue coin is part of G1 and weigh 2 of the coins from G1 against each other once to find rogue coin.
If G1 is the same as G2 but heavier/lighter than G3 rogue coin is part of G3 and should weigh coins against each other once to find rogue coin
Same applies if G1 is lighter/heavier than G2 but same as G3.
All in all, scales are used 3 times
Doesnt determine rogue coin in 3 weighings but is as close as I could get :/
If G1 heavier/lighter than both G2 and G3 then rogue coin is part of G1 and weigh 2 of the coins from G1 against each other once to find rogue coin.
If G1 is the same as G2 but heavier/lighter than G3 rogue coin is part of G3 and should weigh coins against each other once to find rogue coin
Same applies if G1 is lighter/heavier than G2 but same as G3.
All in all, scales are used 3 times
Doesnt determine rogue coin in 3 weighings but is as close as I could get :/