Elton is a candle maker. each 15 centimeter long candle he makes burns evenly for six hours. if elton makes a 45 long centimeter candle, how long will it burn?

Ben frank is an electrician who installs lighting fixtures. he charges (in dollars) his clients 15h+40f15h+40f where hh is the number of hours worked and ff is the number of fixtures installed. how much does ben frank charge when he works 77 hours and installs 99 fixtures?