What is the sum of the first five terms of a geometric series with a1 = 20 and r = 1/4?
express your answer as an improper fraction in lowest terms without using spaces.

Diane owes $387 to her brother. if she debits her bank account $161.25 a month to pay him back, how many months will it take her to pay off the debt?

The graph of h(x)= |x-10| +6 is shown. on which interval is this graph increasing

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