how to find oil Interest rate, in the form of expression, refers to the ratio of the amount of interest to the total amount of borrowed capital in a certain period of time.  the interest rate is the interest level per unit time of the unit currency, indicating the interest rate. Economists have been looking for a theory that can fully explain the structure and change of interest rates. Interest rates are usually controlled by the central bank of the country and administered by the federal reserve board in the United States. Today, interest rates are one of the important tools for macroeconomic regulation. The international monetary fund has strongly defended its gloomy forecast of the UK after brexit, saying a warning of a slowdown in growth is imminent. Positive economic profit is sometimes described as excess profit. There is no risk of this arbitrage. Range and once the two currencies yield, the yield of arbitrage mechanism will make two currencies are equal, that is, different interest rates in the currency of the country there is inherently a trend towards an equalization and trend, it is the interest rate index key aspects of the impact of foreign exchange to, also is our interpretation and grasp the key interest rate index. On the basis of introducing marginal concepts and mathematical argumentation, neoclassical has established a formal "perfect" mathematical model for the neoclassical "laissez-faire order" : general equilibrium. The price is the most important independent variable in this model, which can also be called price mechanism. The process of achieving general equilibrium is also a process of social resources guiding the flow of prices, so the price mechanism regulates the allocation of social resources.