续表 3—6

期数

1 ％ 2 ％ 3 ％ 4 ％ 5 ％ 6 ％ 7 ％ 8 ％ 9 ％ 10 ％ 12 ％ 14 ％ 15 ％

11

.896.804.722.650.585.527.475.429.388.350.287.237.215

12

.887.788.701.625.557.497.444.397.356.319.257.208.187

13

.879.773.681.601.530.469.415.368.326.290.229.182.163

14

.870.758.661.577.505.442.388.340.299.263.205.160.141

15

.861.743.642.555.481.417.362.315.275.239.183.140.123

16

.853.728.623.534.458.394.339.292.252.218.163.123.107

17

.844.714.605.513.436.371.317.270.231.198.146.108.093

18

.836.700.587.494.426.350.296.250.212.180.130.095.081

19

.828.686.570.475.396.331.276.232.194.164.116.083.070

20

.820.673.554.456.377.312.258.215.178.149.104.073.061

25

.780.610.478.375.295.233.184.146.116.092.059.038.030

30

.742.552.412.308.231.174.131.099.075.057.033.020.015

投资(现金流出) ＄3，800 收益(未来的现金流入)

第一年：＄1000×0.917＝＄9l7 第二年：＄1000×0.842＝＄842 第三年：＄1000×0.772＝＄772 第四年：＄1000×0.708＝＄708 第五年：＄1000×0.650＝＄650

＄5000 ＄3889

(未贴现) (贴现)

经计算，＄3889(按 9％利率贴现的收益额)仍比＄3800(初始投资额)要稍微高些。为了将贴现的收益额降低＄89，使其等于初始投资额(＄3800＝＄ 3800 差额为零)，我们所确定的内部报酬率略高于讨论比例 9％。