number of molecules is directly proportional to moles

N = kn(moles)

let weight of O₂ of M then weigth of N₂ is 4M ..

moles of O₂ = M/32                              (molar mass of O₂ is 32)

moles of N₂ = 4M/28                             (molar mass of N₂ is 28)

N₀₂ = k(M/32)             ..............1

N_n2 = k(4M/28)            .............2

dividing both the equations

N_o2/N_n2 = 7/32

approve my ans if u like it