Lumen formula HOW DO I WORK OUT HOW MANY LUMINARES ARE NEEDED?

FOR THE CORRIDOR LEADING TO OFFICES IS 20M LONG BY 3M WIDE AND REQUIRES AN ILLUMINATION LEVEL OF 500 LUX. IT HAS BEEN DECIDED THAT FLUORESCENT FITTINGS ARE TO BE USED. UMING A UTILIZATION FACTOR OF 0.5 AND A MAINTENACE FACTOR OF 0.8,DESIGN THE LIGHTING SCHEME AND SUBMIT A PLAN OF THE LAY OUT OF YOUR LIGHTING SCHEME. HOW MANY LUMINAIRES ARE NEEDED.