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(*) Suppose the production function takes the form y = ART1-a, and we measure income differences between two countries by A = In(yrich ) - In(ypoor ), where yrich is per capita GDP of the rich country and poor per capita GDP of the poor country. Assuming the two countries have the Same productivity, then A is equal to O a (In(krich ) - In(kpoor) ) O (1 - a) In(krich + kpoor) O In(krich) In ( kpoor ) CF In(krich -kpoor) 1-a O (1 - a) (In(krich) + In(kpoor))