Softening is the process of ion exchange. The ions in hard minerals (calcium and magnesium) are exchanged with ions of "soft" minerals such as sodium, which do not produce the hard scale that can damage foodservice equipment. Water softener systems consist of two tanks: a resin tank and a brine tank. The resin tank contains a bed of negatively charged cation resin beads that are coated with sodium (Na*). As hard water passes through this bed, the positively charged calcium (Ca**) and magnesium (Mg**) ions are attracted to and adhere to the resin, causing the sodium ions to release into solution. The calcium and magnesium in the water has now been exchanged for sodium. Since the sodium in the water is harmless to plumbing and equipment, the "softened" water is now ready for use by the operation. During the exchange process, the sodium charge eventually depletes. When near depletion, the softener is regenerated to recover the exchange capacity. To remove the calcium and magnesium from the beads, high concentration sodium solution from the brine tank is drawn through the resin bed. The sodium ions in the solution displace the calcium and magnesium ions, releasing them back into the solution. The sodium in the water has now been exchanged for the calcium and magnesium. These hardness ions are then flushed down the drain. You would like to prepare 1250 kg of a solution composed of 12 % (by weight) NaCl and 88 % water (by weight) to be used in ion exchange regeneration. Two solutions are available for you. The first one contains 5 % (by weight) NaCl and the second one contains 25 % (by weight) NaCl. How much of each solution are mixed to prepare 12 % NaCl solution.