A solution contains both iron(II) and iron(III) ions. A 50.00-mL sample of the solution...

A solution contains both iron(II) and iron(III) ions. A 50.00-mL sample of the solution is titrated with 35.0 mL of 0.0280 M KMnO₄, which oxidizes The permanganate ion is reduced to manganese(II) ion. Another 50.00-mL sample of the solution is treated with zinc, which reduces all the The resulting solution is again titrated with 0.0280 M KMnO₄; this time 48.0 mL is required. What are the concentrations of in the solution?