[tex]Dane:\\P = 120 \ W = 0,12 \ kW\\t = 52\cdot2 \ h = 104 \ h\\k = 0,55\frac{zl}{kWh}\\Szukane:\\K = ?\\\\P = \frac{W}{t} \ \ \rightarrow \ \ W=E_{el} = P\cdot t\\\\W = 0,12 \ kW\cdot104 \ h\\\\\boxed{W = 12,48 \ kWh}\\\\K = k\cdot W\\\\K = 0,55\frac{zl}{kWh}\cdot12,48 \ kWh}\\\\\boxed{K = 6,86 \ zl}[/tex]