real gain

An analyst needs to adjust the nominal GDP for the years 2000 and 2010 into real terms to conclude his comparison analysis. The nominal GDP in 2000 was $672 billion and $1,690 billion for 2010; the real interest rate was 6.79% in 2000 and 3.71% in 2010; the 2000 deflator was 24 and 51 in 2010. What is the real gain?