Amalgam is an alloy of Mercury (Hg), Silver(Ag), tin (Sn) and Zinc (Zn) used in dentistry to fill cavities caused by tooth decay. The amalgam alloy contains 40.0 g of Hg, 11.2 g of Sn, 22.4 g of Ag and 6.4 g of Zn. What is the percentage of each element in the alloy?