An electric lamp is rated 240V, 40W. What is the cost of running the lamp for 72 hours if the electricity authority charges N2.50 per kWh?
The correct answer is: A
Explanation
Cost = \(\frac{Pt}{1000}\) x cost per kWh= \(\frac{40 \times 72}{1000} \times 2.50 = N7.20\)