Two circular frames are kept one above the other. Frame X has a diameter of 16 cm and Frame Y has a diameter of 12 cm. What fraction of the surface of Frame X is not covered by Frame Y?
Select the correct option.
A) 3 / 5	B) 7 / 16	C) 12 / 16	D) 24 / 12	E) 2 / 3

Rationale: the questions asks us to find the surface which is not covered by the frame y i . e . , area of the surface not covered . where as circumference is the length along the edge of the circle , 2 * pi * r implies the length of the curve pi * r ^ 2 implies area enclosed by that curve . . hence area of the circle is considered for this problem area of the frame y = pi * r ^ 2 , where r = 6 = > pi * 36 area of the frame x = pi * 64 surface not covered by the frame y = pi * 64 - pi * 36 = pi * 28 fraction of frame x ' s surface is not covered by a frame y = pi * 28 / total area of the frame x = 28 / 64 = 7 / 16 answer is b
Answer: B