The following series of payments has present value zero: Contributions 10 20 100 ___________ ________ Time (in years) 0 15 30 The present value at time 10 of the payments at time 15 and at time 30 is â’20(1.03) to the power -10 + 100(1.03) to the power -40 = â’14.8818 + 30.6557 = 15.7738 This equals the present value at time 10 of the initial deposit, i.e. 10(1â’d/4) to the power -40 = 15.7738 So, d = 4.5318%