one is a counterfeit that looks identical to the other 11. Using a balance scale and only three weighings, how would you determine which is the counterfeit coin and whether it is heavier or lighter than the real coin ? clues: How many stacks of coins will you use; how many coins per stack; which coins will you test against each other in the 1st weighing; and which ones in the 2nd weighing if the 1st weighing does or doesn't balance. Congratulations to these solvers as of Adam Albright-Hanna, Danny Blanco, Karl Cosner, John & Alex Durski, Albert Frank, Tomasz Grabowski, Joshua Green, Bill Hosch, Steve Kobes, Rabih Assem Kodeih, Napawong Leelaprechalert, LW Luk, Chris Magson, Claire Weglarz and Andrey Zhuravlev. |
