Joe sold tickets for a local concert. Student tickets cost $4 and adult tickets cost $6 each. If 400 tickets were sold for a total of $1900, how many of each type of ticket were sold?

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

If value of cos330° is √3/2 then find tan165°.

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