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probability

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Source: — Data Sufficiency |

by mals24 » Sun Aug 10, 2008 6:35 am
The question asks how many times will head appear at least 4 times if the coin is tossed 5 times. [P(H)=0.6; P(T)=0.4]

HHHHT
HHHTH
HHTHH
HTHHH
THHHH
HHHHH

Probability of Head appearing 4 times and tails appearing once = 5(0.6)^4*(0.4)

Probability of heads appearing all 5 times = (0.6)^5

Total probability = 5(0.6)^4*(0.4) + (0.6)^5
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