Biochemist prepares 2 stocks of sodium phosphate buffer by titrating phosphoric acid with sodium hydroxide. He prepares a 0.10 M solution of sodium phosphate buffer at pH 2.15, and he prepares a 0.10 M solution of sodium phosphate buffer at pH 7.20. If he mixes 51 mL of the pH 2.15 buffer with 32 mL of the pH 7.20 buffer, what will be the pH of the resulting solution? Recall that the pK_as of phosphoric acid are 2.15, 7.20, and 12.35. {Please answer to the nearest hundredth.}