mag 1 oil Modern economy, the interest rate as the price of money, not only restricted by many factors in the economic and social, and changes in interest rates to have a great impact on the economy as a whole, as a result, modern economists are studying the interest rate decision problem, pay special attention to the relationship between the variables and the balance of the economy as a whole, the interest rate decision theory has experienced the classical interest rate theory, Keynes's interest theory, interest rate in loanable funds theory and is-lm analysis as well as the contemporary evolution of dynamic interest rate model, the development process. 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: As we strive to earn an incredible living and pay our charges, there are also crooks who generate a full time income by robbing from unsuspecting victims. Thus, we need to always be on guard from such individuals by securing our private data and making sure that they're not taken from us and useful for crooks' advantages. Canning's view "The tax authorities are investigating allegations of tax evasion after reviewing records of individuals and entities. The authorities are sending a notice to them that they will have to pay a capital gains tax on bitcoin investments and transactions." The city of bentugon salvis, in the southwestern state of Rio grande do, has a reputation as the "capital of Brazilian wine" and has a history of almost 150 years. Nearly 85 per cent of Brazil's wine is produced in more than 700 vineyards, which have a total area of less than 400 square kilometres. The wine is fresh and balanced with cabernet sauvignon, merlot and chardonnay. In his theory, money supply is controlled by the central bank and is an exogenous variable with no interest rate elasticity. At this point, monetary demand depends on people's psychological "liquidity preference".