Ciara mom is planning her birthday party she bought balloons plates and cups sierra's mom bought twice as many plates as cups the number of balloons her mom bought was half the number of cups if her mom bought 84 items how many of each item did she buy

Apinhole camera is made out of a light-tight box with a piece of film attached to one side and pinhole on the opposite side. the optimum diameter d(in millimeters) of the pinhole can be modeled by d=1.9[ (5.5 x 10^-4) l) ] ^1/2, where l is the length of the camera box (in millimeters). what is the optimum diameter for a pinhole camera if the camera box has a length of 10 centimeters