Ch.15_109_006. The internal rate of return method is used to analyze a $831,500 capital investment proposal with annual net cash flows of $250,000 for each of the six years of its useful life. Determine a present value factor for an annuity of $1, which can be used in determining the internal rate of return. (6) Based on the factor determined in (a) and the portion of the present value of an annuity of $1 table presented below, determine the internal rate of return for the proposal. Year 10% 0.909 1.736 2.487 3.170 3.791 4.355 4.868 15% 0.870 1.626 2.283 2.855 3.353 3.785 4.160 20% 0.833 1.528 2.106 2.589 2.991 3.326 3.605