Bài 3:
a. \(\left\{{}\begin{matrix}A1=P1\cdot t=75\cdot8000=600000\left(Wh\right)=600\left(kWh\right)\\A2=P2\cdot t=15\cdot8000=120000\left(Wh\right)=120\left(kWh\right)\end{matrix}\right.\)
b. \(T=T_{mua}+T_{tiendien}=\left(3500+60000\right)+\left[\left(600+120\right)\cdot1500\right]=171500\left(dong\right)\)