Cobalt was used as an internal standard to analyze a sample of titanium with atomic absorption spectroscopy. A mixture was prepared by combining a 6.00 mL Ti solution of unknown concentration with 3.50 mL of a 10.2 ?g/mL solution of Co. The atomic absorbances were measured as 0.155 and 0.195 for Ti and Co, respectively. As a reference, a standard mixture containing 1.94 ?g Co/mL and 1.97 ?g Ti/mL was prepared and measured to have a signal-to-signal ratio of 2.25 Ti: 1.00 Co.

Determine the concentration (moles/L) of titanium in the original unknown solution.