In the early 20th century, famous American economist elvin fisher developed the theory of economic gain. In its book "the nature of capital and yield", first, the concept of yield is analyzed in terms of the performance of earnings, and three different types of benefits are proposed: In the latest "near-term energy outlook," the U.S. energy information administration (EIA) said that in November, conventional gasoline retail prices in the United States averaged $2.56 a gallon, up about 6 cents a gallon on a month-on-month basis. The data initially showed that crude prices were rising. Meanwhile, the U.S. energy information administration (EIA) forecasts that conventional gasoline retail prices in the U.S. will hit $2.59 a gallon this month, up 34 cents a gallon from the previous year. The U.S. energy information agency expects the average U.S. retail price to be at $2.51 a gallon by 2018. Activity-based costing (ABC) is an efficient management technique for assigning and governing the overhead costs. Overhead expense analysis and assignment can be produced more accurate through the use of ABC processes for a wide range of products, for product expenses and profitability analysis as well as for appropriate distribution and control over the overheads. In economic terms, the benefits of holding any two currencies should be equal in the equilibrium of the foreign exchange market, which is: Ri=Rj (interest rate parity). Here, R stands for yield, and I and j represent currencies of different countries. If the benefits of holding two currencies are unequal, you will have A arbitrage: buy A kind of foreign exchange and sell B foreign exchange.