You have six balls - three red and three black. All the red balls weigh differently, i.e. one of them is heavy, the other medium, and the third light. Each red ball has a black twin of the same weight. A heavy and a light ball put together weigh as much as two medium balls.
What is the least number of weighings required on a balancing scale to determine which is which?
(In reply to re: needs checking/ figures can't lie
by Ady TZIDON)
Ah well, back to the drawing board, thank you for your clarification.
It's going to be a loooong night..