The difference between 34 percent and 29 percent is :
34 - 29 = 5 percent.
60 million times 5% = 60 x 0.05 = 3 million
to check:
60 million x 34% = 20,400,000 barrels
60 million x 29% = 17,400,000 barrels
20,400,000 - 17, 400,000 = 3,000,000 barrels
There are 3 million more barrels of gasoline.