The document discusses investment appraisal methods like net present value (NPV) and internal rate of return (IRR). It provides examples to calculate NPV and IRR for a project to determine if it should be accepted. NPV compares the present value of cash inflows to outflows, with a positive NPV meaning the project should be accepted. IRR is the discount rate that results in an NPV of zero. Both are superior to simpler methods like payback period. While NPV is more accurate, IRR is easier for non-financial managers to understand and use to evaluate projects.