Suppose energy costs 0.08 per kilowatt-hour how much would it cost to keep a 40 watt porch light on all night every night for 1 month

Players on the school soccer team are selling candles to raise money for an upcoming trip. each player has 24 candles to sell. if a player sells 4 candles a profit of$30 is made. if he sells 12 candles a profit of $70 is made. determine an equation to model his situation?