Question

In a certain city, electricity costs $0.13 per kW·h.

Answer 1

Answer:

Part a)

cost = $35.58

Part b)

cost = $8.89

Explanation:

Part a)

Annual cost of the incandescent light bulb

Power = 100 Watt

daily use = 7.5 hours

total use of one year

$Energy = 100 \times 7.5 \times 365$

$Energy = 273750 Wh$

$Energy = 273.75 kWh$

cost of energy = $0.13 per kWh

so total cost of energy = $0.13 (273.75)

cost = $35.58

Part b)

25 watt fluorescent bulb

Power = 25 Watt

daily use = 7.5 hours

total use of one year

$Energy = 25 \times 7.5 \times 365$

$Energy = 68437.50 Wh$

$Energy = 68.437 kWh$

cost of energy = $0.13 per kWh

so total cost of energy = $0.13 (68.437)

cost = $8.89

Answer 2

The question is asking to compute the annual cost of electricity to power a lamp post for 7.5 hrs per day with the following power, and base on my calculation, the answers would be the following:
#1. 7,580,769.23
#2. 1,895,195.31
I hope  you are satisfied with my answer and feel free to ask for more if you have questions and further clarifications.