Scientists can find age of ancient objects by the method called radio carbon dating. Bombardment of upper atmosphere by cosmic rays converts nitrogen to the radioactive isotope 14C of carbon with half-life of about 5710 years. Vegetation absorbs carbon dioxide via atmosphere and animal life assimilates 14C through food chains. When the plant or animal dies it ceases replacing the carbon and amount of 14C starts parchment fragment was found that had about 76% as much 14C radioactivity as does plant material on Earth today. Determine age of parchment.