In the case of single independent investments evaluation of the investments by the IRR and NPV methods give the same decision. However, in the case of mutually exclusive investments they rank the investments differently. Mutually exclusive investments often exist in modern property investment for instance, where a owner of a vacant land in order to gauge the highest return for developing the said land, will plan to develop the land in with various development proposals within the building by law and planning constraints. The reason for the difference in ranking is due to the difference in timing and magnitude of the cash flows of the projects. In the case of mutually exclusive investments the NPV method gives correct decision compare to the IRR. The reason for this, lies in their reinvestment assumption rule. The IRR assumes that the project generated cash flows can be reinvested at the IRR rate, whilst the NPV assumes taht the projects can be reinvested at cost of borrowing or capital market alternative rate of return. The assumption in IRR method has no economic basis and is unrealistic, to extent taht such high returns projects simply may not be available in future. Therefore the NPV method decision rule lead to the correct investment decision compared to the IRR, as it measure the investments worth on the absolute terms where the IRR measure it on the relative terms. However, most investment analyst around the world shows preference for the IRR method as compared to that of NPV method. As such the IRR method has to be modified to give a reliable answer as the NPV method. The cost of borrowing or capital market alternative rate used in the discounting process of NPV calculation does not really reflects the real risk involved in the investments. In order to show the real risk involved, we need to determine the market based rate of return of the investments. This market based rate of return can be obtained by identifying the relevant financial and economic variables of the particular investment and determine their relative influence on yields and ultimately returns. The Multiple Regression Analysis model would be of assistance to determine the market based rate of return. The existence of multiple internal rate of returns occur in mixed projects, where there is a mix of both financing and investment. The TRM algorithm and extended yield method can be used to overcome this problem. However, as the TRM algorithm is very complex to understand and compute, the simple extended yield method can be used to solve the multiple rate of return problem.