|
|
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
29 May 2016, 20:54
Kudos
Bookmarks
D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
15%
(low)
Question Stats:
81% (01:21) correct
19%
(01:23)
wrong
based on 101
sessions
History
Date
Time
Result
Not Attempted Yet
2 circles have the same center and the smaller circle’s radius r is 5. If line segment AB is tangent to a smaller circle shown as above figure and the larger circle’s radius is R, what is the length of AB?
1) R=10
2) The circumference of the lager circle is 20π
*An answer will be posted in 2 days.
1) R=10
2) The circumference of the lager circle is 20π
*An answer will be posted in 2 days.
Attachments
1.png [ 11.53 KiB | Viewed 5147 times ]
Pure algebraic questions like this one are no longer part of the GMAT Data Sufficiency syllabus.
For relevant Data Sufficiency questions, please check the Data Sufficiency forum:
Data Sufficiency Forum
Data Sufficiency Forum
29 May 2016, 21:18
Kudos
Bookmarks
MathRevolution
The tangent makes a 90 degree with the radius. We know small radius = 5. If we get the hypotenuse, which is nothing but the radius of bigger circle, we get half of the length of tangent.
so Statement (1) is sufficient.
Statement (2) is also sufficient.
We know the circumference of bigger circle. 2\(/pi\)R = 20\(/pi\). So R is known.
Answer will be D
30 May 2016, 06:49
Kudos
Bookmarks
If we name the center of both circles as O and draw a perpendicular line from O to AB (called OD) then OAD and OBD are two right triangles.
Given:
DO=r=5 (radius of the smaller circle)
AO=R
\(DA^2=OA^2 -DO^2 = R^2 - 5^2 = R^2 - 25\)
Find:
2 x DA - ?
Need:
To find DA we need the value of R
Answer: D
1) R = 10 (we have the value of R) SUFFICIENT
2) C = 20π = 2Rπ, thus R = 10 (we have the value of R) SUFFICIENT
Given:
DO=r=5 (radius of the smaller circle)
AO=R
\(DA^2=OA^2 -DO^2 = R^2 - 5^2 = R^2 - 25\)
Find:
2 x DA - ?
Need:
To find DA we need the value of R
Answer: D
1) R = 10 (we have the value of R) SUFFICIENT
2) C = 20π = 2Rπ, thus R = 10 (we have the value of R) SUFFICIENT
