Answer:
$2.40
Step-by-step explanation:
the unit electricity bill is kilo watt hour.
The 60-watt light bulb has a 400 hour life expectency means it will consume
60×400/1000 = 24 KWh units of electricity. Let us suppose each unit of electricity costs is 10 cents.
Then 24×10 = 240 cents = $2.40