\(A=\left(P1.t1\right)+\left(P2.t2\right)+\left(P3.t3\right)=\left(100.4.30.4\right)+\left(60.4.30.2\right)+\left(1000.4.30\right)=182400\left(Wh\right)=182,4\left(kWh\right)=656640000\left(J\right)\)\(\Rightarrow T=A.1800=182,4.1800=328320\left(dong\right)\)