[MrRubix]

Originally Posted by Flaming_Dingleberry

Well, of course, that's right Rubix, dude how does your brain work? How did you decide to group the bags the way you did?

I've done problems like that countless times before -- it's kinda second nature by now. In my opinion, one of the best ways to learn how to problemsolve is to just solve problems. Over the years, you do so many of them that it becomes easier to figure out when to apply certain logic to certain problems. For instance, in this case it's a good idea to work with triplet groups, since triplets allow for the easiest way to operate on a "if these two groups don't equate, then the residual group has the odd one out" style of solving.