First solve the cost of running the non- energy star model
C = ( $ 0.15 / kWh) ( 0.5 kW) ( 4 hrs /day) 365 day
C = $ 109.5 in a year
Solving the cost of the energy star model
C = ( $ 0.15 / kWh) ( 0.5 kW) ( 4 hrs /day) (0.4) 365 day
C = $ 43.8
Saving in 5 years
S = ( $ 109.5 - $ 43.8) 5
S = $ 328.50
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It is B pair the last one
If Ted needs to lift a heavy load, he should NOT attempt to carry it on his head.
