Final answer:
Ezra's 450-watt rice cooker uses 0.45 kilowatt-hours per day. Over a month (30 days), he consumes a total of 13.5 kilowatt-hours using his rice cooker. This calculation follows the 4-Step Plan of understanding the problem, devising a plan, carrying out that plan, and checking the answer.
Step-by-step explanation:
The student is interested in finding out how much energy in kilowatt-hours (kWh) Ezra's rice cooker uses in a month. The 4-Step Plan for solving problems will be employed: understanding the problem, devising a plan, carrying out the plan, and looking back to check if the answer makes sense. First, we need to understand that power is measured in watts (W) and energy consumption is measured in watt-hours (Wh) or kilowatt-hours (kWh), which is equal to 1000 watt-hours. As Ezra uses a 450-watt rice cooker for an hour a day, we need to calculate the total energy consumption for a whole month.
To find the energy consumption, we use the formula:
E = Pt
Where E is the energy in watt-hours, P is the power rating of the appliance in watts, and t is the time in hours the appliance is used. To convert watt-hours to kilowatt-hours, we divide by 1000.
Step 1: Understand the problem.
Find out the total energy consumption of a 450-watt rice cooker used for an hour a day for a month in kWh.
Step 2: Devise a plan.
Use the formula E = Pt to calculate the energy consumption in watt-hours.
Convert the energy consumption from watt-hours to kilowatt-hours by dividing by 1000.
Multiply by the number of days in a month to get the monthly consumption.
Step 3: Carry out the plan.
Calculate daily energy consumption: E = 450 W × 1 h = 450 Wh.
Convert to kilowatt-hours: 450 Wh / 1000 = 0.45 kWh.
Assuming a month has 30 days, calculate monthly energy consumption: 0.45 kWh/day × 30 days = 13.5 kWh.
Step 4: Look back and check.
Check calculations for correctness.
Ensure that units are consistent and correctly converted.
Ezra's rice cooker uses 13.5 kWh for the month.