juggy, the containers are not full but the amount of milk in A and water in B are equal. hetterika, you could be right : ) i'd like to see the logic behind it though, that's the interesting part, isn't it? slackdemic, i think the 43L is just to throw you off a little.. maybe the solution would be easier if it was any other amount. Or if the question said "any big jar", you'd probably be able to find the answer sooner.