There are two concentric circles with radii 10 and 6. If the radius of the outer circle is increased by 20% and the radius of the inner circle decreased by 50%, by what percent does the area between the circles increase?	Choose the correct answer.
A) 11
B) 111
C) 211
D) 311
E) 411
The area of a circle is piR^2, where R is the radius.   The area of the big circle is 100pi.   The area of the small circle is 36pi.   The area A1 between the circles is 64pi.   When the big circle's radius increases, the new area is 144pi.   When the small circle's radius decreases, the new area is 9pi.   The area A2 between the circles is 135pi.   The ratio of A2/A1 is 135/64 = 2.11 which is an increase of 111%.   The answer is 111.
<result>B</result>
There are two concentric circles with radii 10 and 6. If the radius of the outer circle is increased by 20% and the radius of the inner circle decreased by 50%, by what percent does the area between the circles increase?