Question

a 120 volt,13 watts fluorescent light bulb is operated from 6pm until 10pm every day the cost per kilo watt hour is $0.07. what does it cost to operate this light bulb for 30 days​

Answer 1

4*0.07=energy use per day(x)
(x)*30=energy use in thirty days (y)

Therefore
X=$0.28
Y=$8.4