A 135 mg sample of a metal alloy containing Cu (63.55 g/mol) was dissolved in acid and diluted to a volume of 250.0 mL. Measurement with a Cu+ ISE resulted in a potential of -86.0 mV. Exactly 5.00 mL of 1.00 x 10-2M Cut standard was added to the 250.0 mL solution and the potential on the ISE became -52.7 mV. Calculate the percentage of copper in the alloy.