Americans waste approximately 3.8 million gallons of gasoline each day by voluntarily idling their cars. how many pounds of carbon dioxide does this produce daily? rounded to the nearest tenth of a million pounds.

Theoretically, when 1 gallon of gasoline that does not contain burns, it produces approximately 19.6 pounds of carbon dioxide.

Using direct proportionality;

1 gallon of gasoline = 19.6 pounds of CO2
3.8 million gallons of gasoline = x pounds of CO2

Then;
x = (3.8*10^6 * 19.6)/1 = 74480000 pounds of CO2

Rounding to nearest tenth of million pounds;
x = 74.5 million pounds of CO2

Therefore, idling cars emits 74.5 million pounds of carbon dioxide.