Write an equation for the complete combustion of C9H20

Complete combustion is the oxidation of a fuel where the only products exist as CO₂ and H₂O.
C₉H₂₀ + nO₂ ==> nCO₂ + nH₂O
C₉H₂₀ + 19O₂ ==> 9CO₂ + 10H₂O
use the molecular formula of the hydrocarbon to infer the stoichiometry of the products. The number of oxygens can then be calculated