First you need to know how many pounds of carbon dioxide you get when burning 1 gallon of gasoline. That number is 19.64 pounds
To get the number of pounds released when entire tank is burned you need to multiply gas tank volume and number of pounds you get when 1 gallon is burned.
17.2 * 19.64 = 337.808
Percent decrease = (change in value) / (original value)
change in value = 9965-10100 =-135
We will just use 135 because the negative just that the value decreased
original value = 10100
So 135 / 10100 = .0134
This is a decrease of 1.34%
