Answer: [tex]N43.2[/tex]
Explanation:
Given
Power consumption of bulb and water are [tex]60\ W[/tex] and [tex]240\ W[/tex]
If the Devices are on for four hours
Total power of devices [tex]60+240=300\ W[/tex]
Energy consumed for 4 hours is
[tex]\Rightarrow 300\times 4=1200 Wh\\\Rightarrow 1.2\ kWh[/tex]
For 30 days it is [tex]1.2\times 30=36\ kWh[/tex]
Cost for 30 days [tex]36\times 1.2=43.2\ N[/tex]