The GDO these 3 countries respectively are $ 16.8 trillion, $ 9.2 trillion and $ 4,9 trillion. so the sum of the GDPGDP total = 16.8 + 9.2 + 4.9= 30.9 hence the percentage of the total output of the 3 largest economies is as follows:percentage = ( total gdp / total output of the world ) x 100 percentage = ( 30.9 / 73 ) x 100percentage = 42.33 %