[tex]dane:\\P = 6 \ kW = 6\cdot10^{3} \ W\\W = 2 \ MJ = 2\cdot10^{6} \ J\\szukane:\\t = ?\\\\P = \frac{W}{t} \ \ /\cdot t\\\\P\cdot t = W \ \ /:P\\\\t = \frac{W}{P}\\\\t = \frac{2\cdot10^{6} \ J}{6\cdot10^{3} \ W}\approx0,333\cdot10^{3} \ s\approx333 \ s \approx 5 \ min \ i \ 33 \ s[/tex]
