question (2) Marginal Cost = Change in cost / Change in quantity
= 400 / 100 = $ 4
Q(3) Marginal Benefit = $500-$100 = $ 400
Q(4) Marginal benefit of 2 bags of seeds = $ 1000-$200 = $ 800
Q(5) Marginal Benefit of 3 bags of seeds = $ 1500-$300 =$ 1200
If he is being rational,maximum number of bags = depends on land available