Bill has just returned from a duck hunting trip. He has brought home eight ducks. Bill's friend, John, disapproves of duck hunting, and to discourage Bill from further hunting, John has presented him with the following cost estimate per duck: Camper and equipment: Cost, $1, 400; usable for eight seasons; 10 hunting trips per season $ 140 Travel expense (pickup truck): 100 miles at $0.36 per mile (gas, oil, and tires-$0.22 per mile; depreciation and insurance -$0.14 per mile) 36 Shotgun shells (two boxes) 25 Boat: Cost, $2, 080, usable for eight seasons; 10 hunting trips per season 26 Hunting license: Cost, $30 for the season; 10 hunting trips per season 3 Money lost playing poker: Loss, $20 (Bill plays poker every weekend) 20 Bottle of whiskey: Cost, $15 (used to ward off the cold) 15 Total cost $229 Cost per duck ($229 division 8 ducks) $ 29 Assuming that the duck hunting trip Bill has just completed is typical, what costs are relevant to a decision as to whether Bill should go duck hunting again this season