Question

What is the cost of operating a 3.00-w electric clock for a year if the cost of electricity is $0.0900 per kw · h ?

Answer 1

We must take into account the following change of units:
 $1kw = 1000w 1 year = 365 days 1 day = 24 hours$
 Applying the change of units we have that the electric consumption for 1 year is given by:
 $(3) * (1/1000) * (365) * (24) = 26.28 kw * h$
 Then, the total cost is given by:
 $(26.28) * (0.0900) = 2.3652$
 Answer:
 the cost of operating a 3.00-w electric clock for a year is:
 $ 2.3652