Answer:
The total interest cost is 110, 602 dolars.
Explanation:
The total interest cost has been calculated below. The total interest cost is calculated by multiplying interest rate per month with outstanding loan balance.
Key
M means month there are 240 months in 20 years = 20 *12 =240
Os outstanding loan amount
P payment means monthly installment (principal + interest)
I mean interest per month (7%/12)
PP means payment towards principal
Bal outstanding loan balance = loan amount -principal paid
M OS P I pp Bal
1 128,500 996 749.58 246.68 128,253.32
2 128,253 996 748.144 248.12 128,005.21
3 128,005 996 746.697 249.56 127,755.64
4 127,756 996 745.241 251.02 127,504.63
5 127,505 996 743.777 252.48 127,252.14
6 127,252 996 742.304 253.96 126,998.19
7 126,998 996 740.823 255.44 126,742.75
8 126,743 996 739.333 256.93 126,485.82
9 126,486 996 737.834 258.43 126,227.40
10 126,227 996 736.326 259.93 125,967.46
11 125,967 996 734.810 261.45 125,706.01
12 125,706 996 733.285 262.97 125,443.04
13 125,443 996 731.751 264.51 125,178.53
14 125,179 996 730.208 266.05 124,912.48
15 124,912 996 728.656 267.60 124,644.87
16 124,645 996 727.095 269.16 124,375.71
17 124,376 996 725.525 270.74 124,104.97
18 124,105 996 723.946 272.31 123,832.66
32 120,145 996 700.843 295.42 119,849.18
180 51,011 996 297.567 698.69 50,312.80
181 50,313 996 293.491 702.77 49,610.03
182 49,610 996 289.392 706.87 48,903.16
183 48,903 996 285.268 710.99 48,192.17
184 48,192 996 281.121 715.14 47,477.03
185 47,477 996 276.949 719.31 46,757.72
186 46,758 996 272.753 723.51 46,034.21
187 46,034 996 268.533 727.73 45,306.49
188 45,306 996 264.288 731.97 44,574.51
189 44,575 996 260.018 736.24 43,838.27
190 43,838 996 255.723 740.54 43,097.73
191 43,098 996 251.403 744.86 42,352.88
192 42,353 996 247.058 749.20 41,603.68
193 41,604 996 242.688 753.57 40,850.10
194 40,850 996 238.292 757.97 40,092.14
195 40,092 996 233.871 762.39 39,329.75
196 39,330 996 229.424 766.84 38,562.91
197 38,563 996 224.950 771.31 37,791.60
198 37,792 996 220.451 775.81 37,015.79
199 37,016 996 215.925 780.33 36,235.46
200 36,235 996 211.374 784.89 35,450.57
201 35,451 996 206.795 789.47 34,661.11
202 34,661 996 202.190 794.07 33,867.04
203 33,867 996 197.558 798.70 33,068.33
204 33,068 996 192.899 803.36 32,264.97
205 32,265 996 188.212 808.05 31,456.92
206 31,457 996 183.499 812.76 30,644.16
207 30,644 996 178.758 817.50 29,826.66
208 29,827 996 173.989 822.27 29,004.39
209 29,004 996 169.192 827.07 28,177.32
210 28,177 996 164.368 831.89 27,345.43
211 27,345 996 159.515 836.74 26,508.68
212 26,509 996 154.634 841.63 25,667.06
213 25,667 996 149.725 846.54 24,820.52
214 24,821 996 144.786 851.47 23,969.05
215 23,969 996 139.819 856.44 23,112.61
216 23,113 996 134.824 861.44 22,251.17
217 22,251 996 129.799 866.46 21,384.71
218 21,385 996 124.744 871.52 20,513.20
219 20,513 996 119.660 876.60 19,636.60
220 19,637 996 114.547 881.71 18,754.88
221 18,755 996 109.403 886.86 17,868.03
222 17,868 996 104.230 892.03 16,976.00
223 16,976 996 99.027 897.23 16,078.76
224 16,079 996 93.793 902.47 15,176.30
225 15,176 996 88.528 907.73 14,268.56
226 14,269 996 83.233 913.03 13,355.54
227 13,356 996 77.907 918.35 12,437.18
228 12,437 996 72.550 923.71 11,513.47
229 11,513 996 67.162 929.10 10,584.38
230 10,584 996 61.742 934.52 9,649.86
231 9,650 996 56.291 939.97 8,709.89
232 8,710 996 50.808 945.45 7,764.44
233 7,764 996 45.293 950.97 6,813.47
234 6,813 996 39.745 956.51 5,856.96
235 5,857 996 34.166 962.09 4,894.86
236 4,895 996 28.553 967.71 3,927.15
237 3,927 996 22.908 973.35 2,953.80
238 2,954 996 17.231 979.03 1,974.77
239 1,975 996 11.520 984.74 990.03
240 990 996 5.775 990.48 -0.45