Bill estimates that 20 people will attend the seminar if it does not rain and 12 people will attend if it rains. the weather forecast indicates a 40% chance it will not rain and a 60% chance it will rain on the day of the seminar. determine the expected number of people who will attend the seminar.

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