The gas tank of a 2012 toyota prius holds 11.9 gallons. how many pounds of carbon dioxide are produced by
burning an entire tank of gas?

For this we need to know how much pound of carbon dioxide is produced by burning 1 gallon of gasoline. That number is 19.64 pounds.

Now, all we need to do is to multiply volume of gas that fits car's gas tank.

11.9*19.64 = 233.716 pounds

The answer is 233.716 pounds