your uncle is thinking about opening a bookstore. he estimates that it would cost $60,000 per year to rent the store and another $30,000 on other expenses. In order to be an entrepreneur, he owuld have to quit his job as an economics lecturers that earnes him $200,000 per year. If your uncle thinks he could sell $250,000 worth of books per year, should he open the store if he is rational? Why, or why not? Explain your answer with reference to (a) relevant principle(s) of economics.