Its really urgent!!! Derivation of I=neAVd. ?

let no. of electrons per unit volume=n
charge on an atom=e

no.of electrons in length l of the conductor=n×volume of conductor=nAl

total charge contained in the conductor is
q=neAl

all the electrons which enter the conductor at the right end will pass through the left end of the conductor in time,
t=distance/velocity
=l/vd

therefore,current,
I=q/t=enAl/(l/vd)
=> I=neAvd