An electric iron rated 1000 W, 250 V is used for 2 hours daily for 30 days. If the cost of electricity is ₦50 per kWh, what is the total cost of using the iron for the 30 days?

Energy consumed = Power × Time = 1 kW × 2 h/day × 30 days = 60 kWh. Total cost = 60 kWh × ₦50/kWh = ₦3,000. The rating of 250 V is not needed for this calculation since the power is already given directly.