A music store surveyed 200 customers about their favorite music genre. If 72 customers preferred pop music, how many customers out of 2500 could be expected to prefer pop music?

How do you solve a question like this?

Which one is true about the hexagons ?

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