请问每月投1000元，按每年15%的得利计算，20年后变成150万是怎么计算出来的

这个我会啊，

基金定投收益计算公式：M=a(1+x)[-1+(1+x)^n]/x

M：预期收益

a：每期定投金额

x：一期收益率

n：定投期数(公式中为n次方)

让我们举个例子来看一下吧。

设每月定投500元，年收益12％，定投20、25、26年。

M20≈48万

M25≈89万

M26≈101万

其余数额依此类推

确切的数字是 : 141.37214401510408 万..
我是用计算机计算的..呵呵.公式太久没用 生疏了
year = 1 invest = 1.2 reward = 1.38
year = 2 invest = 2.58 reward = 2.9669999999999996
year = 3 invest = 4.167 reward = 4.79205
year = 4 invest = 5.99205 reward = 6.890857499999999
year = 5 invest = 8.090857499999998 reward = 9.304486124999997
year = 6 invest = 10.504486124999996 reward = 12.080159043749994
year = 7 invest = 13.280159043749993 reward = 15.27218290031249
year = 8 invest = 16.47218290031249 reward = 18.94301033535936
year = 9 invest = 20.14301033535936 reward = 23.16446188566326
year = 10 invest = 24.36446188566326 reward = 28.019131168512747
year = 11 invest = 29.21913116