Ethan jogged around a track and completed 2.75 miles in 45 minutes. what is ethan's speed in miles per hour? answer choices 2.75 miles per hour 2.06 miles per hour 3.67 miles per hour 16.36 miles per hour

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