Advd costs twice as much as a music cd. jack buys 2 dvds and 2 cds and spends $45. determine how much one cd costs, in dollars. [only an alegbraic solution can receive full credit]

Which of the following activities would conserve the most energy? installing a dimmer switch on a light using a blender instead of a food processor hanging clothes to dry on a clothesline instead of ironing them opening a window instead of turning on the air conditioning setting your computer's screen saver to turn on after less time has elapsed