A student used three appliances in her dormitory room: a 1,200-watt iron, which she uses 3.5 hours per month; a lamp with a 100-watt bulb she uses
125 hours per month; and a 700-watt coffee maker, which she uses 15
hours per month.
a. How many kilowatt-hours of electrical energy are consumed in one
month by each appliance?
b. If the local utility company charges 15 cents per kilowatt-hour of
electrical energy consumed, how much does it cost per month to
operate each appliance?

please help I don't understand it