coin is flipped

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coin is flipped

by success1111 » Wed May 13, 2009 8:38 am
If a certain coin is flipped, the probability that the coin will
land heads up is 1/2. If the coin is flipped 5 times, what is
the probability that it will land heads up on the first 3 flips
and not on the last 2 flips?

A. 3/5
B. 1/2
C. 1/5
D. 1/8
E. 1/32
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Re: coin is flipped

by Vemuri » Wed May 13, 2009 8:54 am
IMO E.

Heads up the first 3 flips & not on last 2 means --> HHHTT. This is the only arrangement possible.

So, probability is: 1/(2^5) = 1/32