A circular dartboard of radius 1 foot is at a distance of 20 feet from you. You throw a dart at it and it hits the dartboard at some point Q in the circle. What is the probability that Q is closer to the center of the circle than the periphery?
a) 0.75 b) 1 c) 0.5 d) 0.25
(TCS Question)
Asked by anshu
vijaya lakshmi   d)
7 years ago
somnath   how.plzz xplain.............
7 years ago
Pritam Maity   d) coz it hv 4 circle 1. bull's eye 2. bull 3. triple ring 4. double ring.
so prb is 1/4=0.25
7 years ago
Kirti reddy   Here the distance 20 feet is irrelevant. Don't think of it.
Make a circle of radius r and inside another circle of radius r/2.

Consider the general situation i.e radius = r.​ Now we divide the dart board into two halves. Any point in the inner circle is clearly closer to the center than perifery since we have divided the circle as r/2 and r/2. The dart can hit at any point in the circle. So total sample space is whole area of the circle = (pi)​(r2)----------eq(1). Now we need to find area of the inner circle. Its (pi)*(r/2)2​= (pi)*​​(r2/4)-----------eq(2)​. Probability is (required event)/(sample space) = ​eq(2)/eq(1) = 1/4=0.25.​
7 years ago
Abhishek   (d) 0.25
=(pi(1/2)^2)/(pi.1^2)
=(1/2)^2
=1/4
=0.25
7 years ago
Subhajit Pramanik   0.25
6 years ago
ratikant patra   0.25
6 years ago
akash bhargava   kirti reddy is absolutely right.
6 years ago
sasidhar kumar   ans is 0.25 whole circle area is pi(r^2),inner circle area is pi(r/2)^2 then equation 2 by eqution 1then u get 0.25
4 years ago

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