Consider the Colombian market for soybeans The following gra
Solution
In the absence of Trade: Price = 305, Quantity = 125
Consumer Surplus = area of the green triangle = 1/2*base*height = 1/2*(380-305)*(125-0) = 1/2*75*125 = 4687.5
Producer Surplus = area of the purple triangle = 1/2*base*height = 1/2*(305-230)*(125-0) = 1/2*75*125 = 4687.5
Total Surplus = Consumer Surplus + Producer Surplus
= 4687.5 + 4687.5
= 9375
With International Trade
Pw = 350
Since world price is greater than domestic prices, the seller will export soybean at Pw=350.
Domestic prices will also rise to 350 and hence there will a fall in demand.
As per diagram, At Pw =350
Domestic demand = 50
Total Supply = 200
Thus exports = 200 - 50 = 150
With Free Trade:
Consumer Surplus = 1/2*base*height = 1/2*(380-350)*(50-0) = 1/2*30*50 = 750
Consumer Surplus = 1/2*base*height = 1/2*(350-230)*(200-0) = 12000
Total Surplus = 12750
Change in CS = 750-4687.5 = -3937.5
Change in PS = 12000-4687.5 = 7312.5
Change in Total Surplus = 12750-9375 = 3375

