[問題] 條件機率問題
各位大大們好，本人第一次在本版發言，若有冒犯之處請多包涵
最近選修機率和統計相關課程，練習題目做到此題，感到有點疑惑:
A father asks his son to cut their backyard lawn.Since he does not
specify which of three sons is to do the job, each boy tosses a coin to
determine the odd person, who must then cut the lawn. In the case that
all three gets heads or tails, they continue until reach a decision.
Let p be the probability of heads and q = 1-p, the probability of
tails.
(a) Find the probability that they reach a decison in less than n
tosses.
(b) If p = 1/2, what is the minimum number of tosses required to reach
a decision with probability 0.95.
這題也是一看知道要用P(E)=pP(E|H)+qP(E|T)這類等式，但P(E|H)和P(E|T)要怎麼表示
就不知道了...能否請大大們指點一下嗎?謝謝大家>///<
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