Global World, Inc., a U. S. corporation, has interest expense for the tax year of $200,000, no portion of which is directly allocable to identified property under the regulations. Global World's worldwide asstes have an adjusted basis of $5,000,000 and a value of $10,000,000, of which assets having an adjusted basis of $4,000,000 and a value of $6,000,000 generate U. S.-source income. How much of the interest expense is apportioned to U. S.- source income?