Final answer:
The incorrect statement is that Mike and Maria must trade equal numbers of phones and meals to benefit. They should specialize in the production of goods where they have a comparative advantage, and then trade to improve both of their consumption possibilities.
Step-by-step explanation:
The statement that is not true is that Mike and Maria will both gain only if they trade the same number of phones for the same number of meals. This is based on understanding the principle of comparative advantage and specialization. While Mike should indeed produce more food and fewer phones, and Maria should produce more phones and fewer meals, the key to their gain from trade is that each specializes in producing the good for which they have a comparative advantage. By doing so, both can increase their total output, and through trade, they can improve their consumption possibilities.
Division of labor increases productivity by allowing workers to focus on tasks that make the best use of their abilities and skills. In the case of specialized workers like a baker and a chef, if each specializes in their best task, the kitchen can produce more meals efficiently because each worker's productivity is maximized. This principle extends to economies at the macro level, where countries specialize in producing goods for which they have a comparative advantage and engage in international trade, thereby increasing overall welfare.