In an analysis to determine the Quantity of Calcium in calcium supplement tablets, twenty tablets, each claiming to contain 600mg of calcium were finely powdered. A quantity of powder containing 50mg of calcium  was extracted with 50mL of carbon dioxide free water and 5mL of 1M HCl solution in a conical flask. The mixture was gently heated for two minutes, allowed to cool and reacted 50mL of 0.05M Di-sodium Edetate Vs. The pH of the resulting solution was brought to neutral followed by the addition of 10mL of Ammonia buffer pH 10 and 50mL of carbon dioxide free water.

The excess Disodium EDTA were titrated  with 26.8mL of 0.05M ZnCl₂Vs using 0.1mL of mordant black T solution as indicator to a permanent pink color end point.

Given that each mL of Disodium EDTA is equivalent to 2.004mg of Ca²⁺, calculate the actual quantity and the percentage yield of calcium in each tablet.