An arrow is placed 28.7 cm in front of a convex lens (f=15.0 cm). The convex lens is followed by a concave lens (f= 21.5 cm) 12.8 cm fro the convex lens. A third lens, convex in nature, is placed 165 cm after the concave lens. An image on a screen appears 2.98 m from the object.
a) What is the focal length of the third lens?
b) What is the magnification of the image?