A 50.0-mL solution containing Ni2+ and Zn2+ was treated with 25.0 mL of 0.045 2 M EDTA to bind all the metal. The excess unreacted EDTA required 12.4 mL of 0.012 3 M Mg2+ for complete reaction. An excess of the reagent 2,3-dimercapto-1-propanol was then added to displace the EDTA from zinc. Another 29.2 mL of Mg2+ were required for reaction with the liberated EDTA. Calculate the molarity of Ni2+ and Zn2+ in the original solution.