Hint 14-53

1 ppm of a compound is 1mole cmpd / 1 x 10⁶ moles of the total mixture.
As a close enough approximation we can work in grams.
You will need to sum all the masses to get the mass of the mixture.
Convert this to 1 x 10⁶ grams and then using the same conversion factor work
out how much CO₂ is present in 1 x 10⁶ grams of mixture.