If a moose were chasing you through the woods its enormous mass would be very threatening but if you zigzagged then it great mass would be to your advantage explain why

The illuminance of a surface varies inversely with the square of its distance from the light source. if the illuminance of a surface is 120 lumens per square meter when its distance from a certain light source is 6 meters, by how many meters should the distance of the surface from the source be increased to reduce its illuminance to 30 lumens per square meter?