125. Solving a chemistry problem

8. What mass of a substance containing 60% NaCl and 37% KCl should be taken for analysis so that after adding 40.000 ml of 0.1000 M AgNO3, excess silver can be titrated with 15.00 ml of NH4SCN solution in the presence of NH4Fe(SO4)2 ( 1 .00 ml of NH4SCN solution is equivalent to 1.10 ml of AgNO3 solution).