An unknown amount of water is mixed with 350 mL of a 6 M solution of NaOH solution. A 75 mL sample of the resulting solution is titrated to neutrality with 52.5 mL of 6 M HCl. Calculate the concentration of the diluted NaOH solution. What volume of water was added to the 350 mL of NaOH solution? Assume volumes are additive. Answer in units of mL.