Determine the hydrocarbon fuel model cnhmnbspfor this

Question

An Orsat analysis of the combustion of a strange unearthly hydrocarbon gas produces a (dry) result of 5.00% each for CO₂, CO, and O₂, with N₂ making up the remainder. Determine

a. The hydrocarbon fuel model C_nH_m for this strange and somewhat putrid gas.

b. The mass composition of this gas.

c. The percent of excess air used in the combustion.