If X is the center of circle A and Z is the center of circle B, is the

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https://gmatclub.com/forum/download/file.php?id=58868 If X is the center of circle A and Z is the center of circle B, is the circumference of circle B > 10? (1) Radius of the circle A = 9 (2) XY = 2YZ 2020-11-10_11-39-39.png

IanStewart · Answer

Statement 1 is not sufficient, since we have no idea where point Y is, so the radius of the small circle can be nearly zero, or can be quite large. Statement 2 is clearly not sufficient, since we have no actual numbers. Using both Statements, we know the ratio of XY to YZ is 2 to 1, from Statement 2, so the length YZ is 1/3 of the total length XZ, which is 9. So the length of YZ is 3, and since that's the radius of the small circle, we can find its circumference and answer the question. So the answer is C.

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winterschool · Answer

Statement 1 : XZ = 9

Not sufficient

Statement 2: XY = 2 YZ

if xz = 3, yz = 1 , circumference of circle B <10
if xz = 9 , yz = 3, circumference of circle B > 10

Not sufficient

Statement 1+ Statement 2:

xz = 9 , yz = 3, circumference of circle B = 2pi*3 = 6*pi ~18>10

Sufficient

Answer C

If X is the center of circle A and Z is the center of circle B, is the

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