calculate net profit Full market competition will make economic activity full of vigor and vitality. Marx's interest rate determinism is based on the source and essence of interest. Marx reveals that interest is a portion of the surplus that the capitalist who lends capital is divided from the capitalist who borrows the capital, and the profit is the transformation form of the surplus value. In 2010, China overtakes Japan being the other world's economy. According to economists, China remains to be a developing country with fast pace of growth. Data released that Japan\'s gross domestic product is $1.286 trillion while it is worth $1.335 trillion for China. Another source demonstrates Japan keeps growing at 2-3 percent in compared with 10 % a year of China. Accounting earnings include only realized gains, and exclude unrealized gains and losses, the economic benefits will be enterprise's operating earnings and are favorable to the same treatment, regardless of whether they have been implemented. Thus, in general, accounting gains are less than economic gains, and the difference is mainly in the interest. Passenger car: in its design and technical features, it is mainly used to carry passengers and their carry-on luggage and (or) temporary items, including the driver's seat, not more than 9 seats. It can also draw a trailer. Classified into ordinary passenger cars, live senior passenger cars, passenger cars, small passenger car, convertible, warehouse back passenger car, station wagon, multipurpose passenger vehicles, short head special passenger cars, cross-country passenger cars and passenger cars, etc. 11 class.