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Probability Question

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Probability Question

by ruchisharma » Fri Aug 13, 2010 6:57 am
When tossed, a certain coin has equal probability of landing on either side. If the coin is tossed 3
times, what is the probability that it will land on the same side each time?

A. 1/8 B. ¼ C. 1/3 D. 3/8 E. ½
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by kmittal82 » Fri Aug 13, 2010 7:02 am
The question is simply asking whats the probability of having either 3 heads or 3 tails in 3 coin tosses:

P(3 heads) = 1/2 x 1/2 x 1/2 = 1/8

P(3 tails) = 1/2 x 1/2 x 1/2 = 1/8

P(3 heads or 3 tails) = p(3 heads) + p(3 tails) = 1/8 + 1/8 = 2/8 = 1/4
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