A travel agent calculates the cost of a trip to Paris using this formula C = p(t + 30) C is the total cost in pounds
p is the number of people
t is the cost of the trip per person
Use this formula to calculate the total cost if p = 2 and t = 245.

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