The appropriate discount rate is 8.05%. Exclude the 50 already spent on design. Debt is 30% of financing at 5%, equity costs 10%, giving WACC = 0.30 × 5% × 0.70 + 0.70 × 10% = 8.05%. Cannibalisation starts at 80 and grows 10% each year. Alternative repeatable project Beta has cash flows −2,200, 910, 1,010 and 1,040 at years 0–3.
CFdisposal=400−0.3(400−(2500−500×5))=280.00 NPV=(−2,500)+1.0805464+1.08052582.40+1.08053675.04+1.08054786.82+1.080551,305.32 NPV = 427.00. Accept.