17. Suppose a family replaces ten 60-watt (0.06 kW) incandescent bulbs with ten 30-watt (0.03 kW) fluorescent bulbs. If each bulb was used for 4 hours per day and the cost of electricity was 10.0 ¢/kWh, how much money would they save in a year?(2 points)
First, we need to calculate the total energy consumed by the incandescent bulbs.
The total energy consumed by one incandescent bulb per day is 0.06 kW x 4 hours = 0.24 kWh.
The total energy consumed by the ten incandescent bulbs per day is 0.24 kWh x 10 = 2.4 kWh.
The total energy consumed by the ten incandescent bulbs per year is 2.4 kWh x 365 days = 876 kWh.
The cost of the energy consumed by the ten incandescent bulbs per year is 876 kWh x 10.0 ¢/kWh = $87.60.
Next, we need to calculate the total energy consumed by the fluorescent bulbs.
The total energy consumed by one fluorescent bulb per day is 0.03 kW x 4 hours = 0.12 kWh.
The total energy consumed by the ten fluorescent bulbs per day is 0.12 kWh x 10 = 1.2 kWh.
The total energy consumed by the ten fluorescent bulbs per year is 1.2 kWh x 365 days = 438 kWh.
The cost of the energy consumed by the ten fluorescent bulbs per year is 438 kWh x 10.0 ¢/kWh = $43.80.
Therefore, the family would save $87.60 - $43.80 = $43.80 in a year by replacing the incandescent bulbs with fluorescent bulbs.