4 13) While shopping for a gift, you find the perfect wallet on sale
for 89% off its original $5.62 price. How much will you pay for
the wallet?
I
14) A wallet is marked with a sale sticker saying it is 76% off
The original price is $57.41. What is the sale price?
15) Originally priced at $48.69, a wallet was found on a 10% off
rack. What is the sale price of the wallet?

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