Answer:
NPV is $771,739
Explanation:
As we know that:
Net Present Value = Present Value of Cash inflow (STEP 1) - Present Value of Cash outflow
<u>STEP 1. Present Value of Cash Inflow</u>
Here 
Present Value of Cash Inflow = Annuity of Annual Cash flow    - PV of Scrap Value
Annual Cash flow is $346,000 ($230,000  +   ($786,000 - $90,000)/6)
So 
Annuity of annual cash inflow = $346,000 * Annuity Factor
Here 
Annuity Factor for 6 years is 4.3553
Now this means that:
Annuity of annual cash Inflow = $346,000 *  4.3553 = $1,506,934
Present Value of Residual Value ($90,000 * 0.5645) =<u> </u><u>$50,805</u>
Present Value of cash inflows                                        $1,557,739
Now putting values in the above equation, we have:
Net Present Value = $1,557,739   -    $786,000
Net Present Value = $771,739