The chance of a head occurring in a certain biased coin is twice that of the tail occurring if the coin tossed 5 times. What is the probability of at most 1 tail occuring in the 5 tossed?
Pr(H)=2/3
pr(T)=1/3
pr(T<2)=1/3*(2/3)^4 + (1/3)^0 * (2/3)^5
= 1/3^5 2^4(1+2)=(2/3)^4=.198
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