What is the monthly (30 days) energy cost (in
$) of leaving a 40-W bulb on continuously if
electricity costs 21¢ per kWh? Round final
answer to the nearest cent.

Respuesta :

Explanation:

Power= 40 W

cost=21¢/kWh

t=1 month=30 days = 720h

Energy= power*time

E= 40W* 720h = 28800kWh

Cost= Energy*rate

cost= 28800kWh*21¢/kWh

cost=604800¢