Probability

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Probability

by Ramasubramanian » Mon Dec 13, 2010 11:39 am
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) 1/4 b) 1/2 c)3/4 d) 1/3
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by Night reader » Mon Dec 13, 2010 12:01 pm
Ramasubramanian wrote: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) 1/4 b) 1/2 c)3/4 d) 1/3
number of outcomes -?
number of favorable outcomes -?
assumption: events are mutually exhaustive and independent
therefore, P(Q)=1/2

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by towerSpider » Mon Dec 13, 2010 12:24 pm
Ramasubramanian wrote: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) 1/4 b) 1/2 c)3/4 d) 1/3
overall: p

.25p

.25/1=1/4

1/4 IS ANSWER.

PS: this is not gmat question. 20 ft given is IRRELEVANT. p for pi (aprrox. 22/7)