how was the NPV total 8.70271 calculated can someone tell me step by step heres the cashflow

Calculation of yearly Cash Flow: No. of units Sales (4485 Variable cost Fixed cost 64000 106000 87000 78000 54000 31040000 5141000042195000 37830000 26190000 13120000 21730000 17835000 1599000011070000 5100000 5100000 5100000 5100000 5100000 6208000 102820008439000 7566000 5238000 2857 4928571 4928571 4928571 4928571 6208000 10282000 8439000 7566000 WC Retunm 1683429 15577429 16174429 12684429741942 Tax @30% Profit after tax Cash flow 505028.7 4673229 4852329 3805329 2225829 1178400.3 10904200 11322100 8879100 5193600 61069713 15832771 16250671 1380767110122171 Calculation of Pyback period: in millions Cumulative PV factor PV of Year Cashflow Cash flow @12% 35.45 35.45 6.12 29.33 0893 5.46516 cash flow 35.45 5.83-13.5 0.797 12.61651 16.25 2.75 13.8 10.12 26.67 675.73804 0.712 11.57 0.635 8.763 16.55 8,70271 Pay back period +13.5/16.25 3+0.83 3.83 years Profitability Index (NPV+Initial Investment/ Initial Investment (8.703 M+35.45 My35.45M 1.25 NPV 8.703 M