Please show work other than Yahoo answerSolutionVd is drift

Please show work (other than Yahoo answer)

Vd is drift velocity
i is current
n is the number of charge carriers per unit volume
A is the cross sectional area
q is the charge of the charge carriers
= 1.602 × 10–19 C

A = (.0015)² = 7.07e-6 m²
Vd = 1200 / 1e29*1.6e-19*7.07e-6
Vd = 1200 / 11e4
Vd = 10e-3 m/s = 10mm/s

to move 10 inch (.25m or 250mm)
250 / 10mm/s = 25 sec