Astore is having a sale on jelly beans and trail mix. for 8 pounds of jelly beans and 4 pounds of trail mix, the total cost is $21 . for 3 pounds of jelly beans and 2 pounds of trail mix, the total cost is $9 . find the cost for each pound of jelly beans and each pound of trail mix.

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