A 25.0-mL sample containing Cu 2+ gave an instrument signal of 25.2 units (corrected for a blank) when exactly 0.500 mL of XXXXXXXXXXM Cu(NO 5 ) 2 was added to the solution, the signal increased to...

A 25.0-mL sample containing Cu²⁺
gave an instrument signal of  25.2 units (corrected for a blank) when exactly 0.500 mL of 0.0275 M Cu(NO₅)₂
was added to the solution, the signal increased to 45.1units. Calculate the molar concentration of Cu²⁺
assuming that the signal was directly proportional to the analyte concentration.