Imagine that two neighbors (A and B) independently and negligently start fires, both of which spread to plaintiff's property, one destroying plaintiff's $100,000 house and the other destroying plaintiff's $100,000 barn. Plaintiff successfully sues both. Imagine that defendant B has no money or assets. Under the rules of apportionment of liability, how much can plaintiff collect from each defendant? Would the result be different if the fires had merged to destroy both house and barn together? What would be a fair result?