How old am i if 400 reduced by 2 times my age is 244?

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

Sum of the interior angles of a pentagon

At your job you're paid $50 per week plus $3 per sale at least how many saled do you need to make in order to have over $250