Final answer:
To find the cost of using a 1600-W coffee maker for 19 minutes and a 1100-W microwave for 3.5 minutes at a cost of 7¢ per kWh, we calculate the energy consumed by each appliance and then multiply the total kWh by the cost per kWh, resulting in approximately 4¢ total cost.
Step-by-step explanation:
To calculate the cost of using a 1600-W coffee maker for 19 minutes and a 1100-W microwave oven for 3.5 minutes at an electrical cost of 7¢ per kWh, we need to convert the power and time into kilowatt-hours (kWh). The formula for energy consumption in kWh is Power (in kW) × Time (in hours).
First, we convert the power of the appliances to kilowatts (kW):
- Coffee maker: 1600 W = 1.6 kW
- Microwave oven: 1100 W = 1.1 kW
Next, calculate the time in hours:
- Coffee maker: 19 min = 19/60 hour = 0.3167 hour
- Microwave oven: 3.5 min = 3.5/60 hour = 0.0583 hour
Then we calculate the energy consumption:
- Coffee maker energy: 1.6 kW × 0.3167 hour = 0.5067 kWh
- Microwave oven energy: 1.1 kW × 0.0583 hour = 0.0641 kWh
Now, combine the total energy consumption and calculate the cost:
Total energy = 0.5067 kWh (Coffee maker) + 0.0641 kWh (Microwave oven) = 0.5708 kWh
Total cost = 0.5708 kWh × 7¢/kWh
Total cost = 3.9956¢
Therefore, the total cost for using both appliances is approximately 4¢.