Six balls confront you: two red, two green, and two blue. In each color pair you know that one ball is heavier than the other. You also know that all three of the heavier balls weigh the same, as do all three of the lighter balls. The six balls (call them R1, R2, G1, G2, B1, and B2) are otherwise indistinguishable. You have only a balance scale. With no more than two weighings on the scale, how can one identify the heavier and the ligheter balls in all three pairs?
Anybody got a clue?