Lalith and shekhar each have a square field of different size. they built a wire fence around their respective fields without any gap or overlap. lalith used 8 bundles of fencing wire each of length 20m which cost him a total of rs.800.shekhar used some other bundles each of length 30m which cost him a total of rs.300.each paid the same price per meter wire. what is the difference between the length of the sides of their field