Which answer would score higher? Not sure where to start? Explain this Answer A 162 kJ = 162000 J. The operating time is 1.5 min, so P = E/t = 162000 ÷ 1.5 = 108000 W for the hotplate. Answer B 162 kJ = 162000 J. The operating time is 1.5 × 60 = 90 s, so P = E/t = 162000 ÷ 90 = 1800 W for the hotplate.