Answer:
$8640
Step-by-step explanation:
kwh = P×t...................... Equation 1
Where P = power in watts, t = time in hours.
From the question,
Given: P = 100 Watts, t = 720 hours
Substitute these values into equation 1
Therefore,
The total kilowatt hour used by the patio light = 100×720
= 72000 kwh.
From the question,
If, 1 kwh ⇒ $0.12,
Then, 72000 kwh ⇒ $(0.12×72000)
= $8640
Hence, the patio light cost kevin $8640