Referring to the scenario and the problems of the travel agent the only way a firm can alter output is by altering the amount of variable input. The variable input is conventionally presumed to be labor. Output is mentioned to as the merchandise of labor. The total merchandise of work is the allowance of yield produced. The total merchandise bend is the short run connection between the allowance of yield made and the amount of work used. Capital which is repaired serves as a capability constraint. we start our study of economics with four principles of individual decision making. ...