Answer:
54 Kobo
Explanation:
Units of electricity are measured in kilowatt hours (kWh).
Given information:
- 900 watt electric iron
- Appliance usage = 4 hours a week for 5 weeks
- Unit cost of electricity = 3 Kobo per kWh
Step 1
Convert the wattage of the electric iron from watts to kilowatts.
1000 watts (W) = 1 kilowatt (kW)
⇒ 900 watts = 1 ÷ 1000 = 0.9 kilowatts
This means that the power consumption of the electric iron is 0.9 kW per hour of use.
Step 2
Total hours spent pressing clothes:
= 4 hours per week for 5 weeks
= 4 × 5
= 20 hours
Total power consumption:
= number of kW × number of hours
= 0.9 × 20
= 18 kWh
Step 3
To find the total cost, multiply the total kWh by the cost per kWh:
⇒ Cost = 18 × 3 = 54 Kobo
