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Probability of coins

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Probability of coins

by vishubn » Mon Oct 20, 2008 10:39 am
I am sure it might be the easiest ... but i am no game for probablity :( please comment....


A coin that is tossed will land heads or tails, and each outcome has equal probability. What is the
probability that the coin will land heads at least once on two tosses?

A. 1/4
B. 1/3
C. 1/2
D. 2/3
E. 3/4

OA E
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by dmateer25 » Mon Oct 20, 2008 10:47 am
P(heads at least once) = 1 - P(Neither being heads)

P(Neither being heads) = (1/2)^2 = 1/4

P(heads at least once) = 1 - 1/4 = 3/4
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by stop@800 » Mon Oct 20, 2008 12:42 pm
HH
HT
TH
TT

so you need to select 3 out of 4
hence 3/4
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