A car's ventilation system has various controls. The fan control has four settings: off, low ,medium, high. The air stream can be set to come out at the floor, through the vents, or through the defroster. The air conditioning button can be either on or off. The temperature control can be set to cold, cool, warm, or hot. And finally, the recirculate button can either be on or off.
In how many different ways can these various controls be set?
Note: Several of these settings result in the same effect since nothing happens if the fan control is off. However, the problem asks for the number of different settings of the controls, not the number of different ventilation effects possible.