#### Answer

200,000 gal

#### Work Step by Step

To find the increase in super unleaded gasoline sales from 2009 to 2013
We need to first find the amount of gasoline in each year from 2009 to 2013.
In 2009 the super unleaded gasoline sale was 400,000 gal
In 2010 it was same there was no increase in the gasoline sales
So difference between 2009 and 2010 = 0
now in 2011 it increases to 550,000 gal
So difference between 2011 - 2010 = 550,000 - 400,000 = 150,000 gal
Again in 2012 it increases to 650,000 gal
Difference between 2012 and 2011 = 650,000 gal - 550,000 gal = 100,000 gal
in 2013 it decrease to 600,00 gal
So difference = 600,000 gal - 650,000 gal = - 50,000 gal
Now the total increase = 0 + 150,000 + 100,000 - 50,000 = 200,000 gal
Therefore the increase in super unleaded gasoline sales from 2009 to 2013 is 200,000 gal