Firstly, KG is a maesure of MASS not weight, though they are used (mistakenly) interchangeably in Earth's gravity.
1 KG = 2.204622 LBs in Earths Gravity (this IS a measure of weight).
Given: . 1 + 1/2 w = w subtract 1/2 w from both sides
1= 1/2 w and thus w = 2 kg. (4.409245 pounds)