Circles X and Y are concentric. If the radius of circle X is five times that of circle Y, what is the probability that a point selected inside circle X at random will be outside circle Y?
Choose the correct choice:
A) 13
B) Pi/3
C) Pi/2
D) 5/6
E) 24/25
Small circle radius = a, so area = PI a ^ 2   Large circle radius = 5a, so area = 9. PI a ^ 2   Area of shaded region = 25PI a^2 - PI a^2 = 24 PI a^2   So, probability = ( 24 PI a^2 ) / (25 PI a^2 )   = 24/25 = Answer = 24/25
<result>E</result>
Circles X and Y are concentric. If the radius of circle X is five times that of circle Y, what is the probability that a point selected inside circle X at random will be outside circle Y?