At 7..35 cents per kilowatt-hour, what does it cost to operate a 10.0 hp motor for 8.00 h?

What does it cost to leave a 75 W light burning 24 hours a day?

1 Answer
Feb 17, 2018

Well, it looks like you have two different questions here...

Explanation:

I will split the questions into two parts.

Question #1.# "At 7.35 cents per kilowatt-hour, what does it cost to operate a 10.0 hp motor for 8.00 h?"

Question #2.# "What does it cost to leave a 75 W light burning 24 hours a day?"

#1.#

We know that #1# horsepower is equivalent to #~~0.75kW#.

So, #10 \ "hp"=7.5kW#

For #8h#, that would be a total of #7.5kW*8h=60kWh#

We know that it costs #7.35# cents to run #1kWh#.

So, it would cost #60*7.35c=441c=$4.41# in total.

#2.# If the rate (#7.35c# per #kWh#) is still the same as in question #1.#, then we proceed as follows:

We know that #1kW=1000W#, #:.75W=0.075kW#. For #24# hours, that would be a total of

#0.075kW*24h=1.8kWh#

So, it would cost a total of #1.8*7.35c=13.23c#

So, it would cost #13.23~~13# cents in total to run the light bulb for a whole day.