A 0.3146-g sample of a mixture of NaCl(s) and KBr(s) was dissolved in water. The resulting solution required 40.70 mL of 0.08765 M AgNO3(aq) to precipitate the Cl^- (aq) and Br^- (aq) as AgCl(s) and AgBr(s).
Calculate the mass percentages of NaCl(s) in the mixture. (% NaCl)