Answer:
75
Step-by-step explanation:
Opportunity cost of good A for country X = Total B given up/Total A gained = (10-0)/(300-200) = 10/100 = 0.1
Opportunity cost of good A for country Y = Total B given up/Total A gained = (30-0)/(60-40) = 30/20 = 1.5
So, Country A has comparative advantage in production of good X. Thus it will produce only X = 300. Amount traded = 125. So, amount left = 300-125 = 175. Extra X consumed by A = 175 -100 = 75