Answer:
12.90%
Step-by-step explanation:
Annual average investment = (Initial investment + Salvage value) / 2
Annual average investment = ($280000 + $30000) / 2
Annual average investment = $155,000
Accounting rate of return = Annual after-tax net income / Annual average investment
Accounting rate of return = $20,000 / $155,000
Accounting rate of return = 0.1290322581
Accounting rate of return = 12.90%