Abigail works in the shipping department of a toy factory that makes radio-controlled helicopters. Small helicopters weigh 1 kilogram each, and are shipped in a container that weighs 7 kilograms. Large ones, on the other hand, weigh 3 kilograms apiece, and are shipped in a container that weighs 5 kilograms. If these boxes can hold a certain number of helicopters each, all of the packed containers will have the same shipping weight. What would the total weight be? How many helicopters would fit in either container?