How the result of $117,415 is calculated?

I can not understand the way calculations are build

The correct answer is shown. Using the information in the following table and a discount rate of 10%, the firm's present value of incremental benefits is $ 117415. (Omit the dollar sign and commas. Round to the nearest whole number) Year Tax Shield Benefits from Depreciation After-tax Cost Savings $4,536 $58,000 $15,330 $58,000 X Sorry, your ansv is incorrect. Read about this You wrote X 83868 instead of v 117415. Challenge OK