Answer:
35.5 % NaCl
Explanation:
Total mass of mixture = 30.126 g
Mass of sand = 15.976 g
Mass of iron = 3.455 g
Mass of NaCl = ? → Total mass - 15.976 g - 3.455 g = 10.695 g
% mass of NaCl in the sample → (Mass of NaCl / Total mass) . 100
(10.695 g / 30.126 g) . 100 = 35.5 %