Determine the empirical formula of a compound that contains 30.45% nitrogen and 69.55% oxygen

I might not be right but I think the empirical formula is NO2

> b takes place in the gas phase in an isothermal tubular reactor. the feed is one mole of a per one mole of c, an inert. the entering temperature and pressure are 427°c and 10 atm, respectively. the gas constant r = 0.08206 atm · l/mol · k.

i think it's letter a.