R烘=U^2/P=220^2/1000=48.4ΩP洗=250WW总=P1t1+P2t2+P3t3+P4t4+P5t5 =1*0.5+0.1*0.6+0.5*0.1+0.25*1/6+0.25*1/3 =0.735kwh
