Question

In an area in which electricity costs 8 cents/kilowatt-hour, a 5 kW clothes dryer runs for 90 minutes to dry a load of laundry. How much did it cost to dry these clothes?
These are the choices
$0.20
$0.30
$0.45
$0.60
Please help!!!!!!!!!!!!

Answer 1

firstly find kilowatt*hour
so you have 5*1.5(90min=1.5hours)
7.5*8 =60
so the cost is 60 cent
8cent/kilowatthour*7.5kilowatt hour