Marcab wrote:
sorry....its R/2.
its been corrected in the original post.
Great now it makes sense
Basically in the question we are looking for probability of point lying in Green region in the attached figure.
Since the radius of Grean Circle is R and radius of red circle is R/2. Hence the area of greeen region =
\(pi R^2 - pi (r/2)^2\)
\(= 3/4 pi R^2\)
Also area of circle with radius R\(= pi R^2\)
Hence probability of point lying in green region =\(3/4 pi R^2 / pi R^2\)
= 3/4
Hence Ans B it is.
Hope it helps.
Attachments
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