-- The mass of the exhaust products belched from the tailpipe is
equal to the
sum of the masses of the gasoline slopped into the fuel tank,
the air inhaled by
the carburetor, and any ancillary fluids that leak into the
combustion cylinders.
-- The mass of the people that get out of the car is equal to
the sum of the masses of
the people that get into it and the food and drinks they bring
with them and consume
en route.