Answer: (i) $20 per model
(ii) $27 per model
(iii) Ginny has a comparative advantage in building models.
Explanation:
A country or a firm has a comparative advantage in producing a commodity if the opportunity cost of producing that commodity in terms of other commodities is lower than the other country or firm.
Opportunity cost is the benefit that is foregone for an individual by choosing one alternative over other alternatives available to him.
If the opportunity cost is lower for an individual then this will benefit him whereas if the opportunity cost is higher then this will not benefit the individuals.
Therefore,
Ginny's Opportunity cost of producing one model =
= $20 per model
Eric’s opportunity cost of building models = $20 + 35% of $20
= $20 + $7
= $27 per model
Hence, Ginny has a comparative advantage in building models because Ginny's opportunity cost of building model is lower than Eric's opportunity cost.