Discussion of Question with ID = 041 under Areas

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A gun is fired towards a circular board consisting of two concentric circles of radii 12 and 3 cm. If each bullet is able to hit the board, what is the probability that it will strike the ring, i.e., the area between the inner and outer circles?









Ans: a

The area of the ring is equal to the difference of the areas of the two circles. π($12^2 - 3^2$) = 135π sq. cm. The total area is π × 122 = 144π. The probability of hitting the ring is ${135π}/{144π}$ = ${15/16}$.

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