1. A coin is located 19.6cm to the left of a converging lens (f = 16.5cm). A second, identical lens is placed to the right of the first lens, such that the image formed by the combination has the same size and orientation as the original coin. Calculate the separation between the lenses. This one I'm pretty lost on. I know that 1/do + 1/di = 1/f, but the 'same size and orientation' is particularly tripping me up. 2. A person holds a book 27.7cm in front of the effective lens of her eye; the print in the book is 1.80mm high. If the effective lens of the eye is located 1.75cm from the retina, what is the size (including the sign) of the print image on the retina? I thought the equation to solve this was hi/ho=-(di/do), but I'm apparantly mistaken as using this equation produces an incorrect result. Of course, I could have misused it. Any help is appreciated, and thanks.