[問題] 機率問題

[coldtyan ()]

1.Die A has 4 red and 2 white faces,whereas die B has 2 red and 4 white faces.
  A fair coin is flipped once. If it lands on heads, the game continues with
  die A ; if it lands on tails, then die B is uesd.
question:
  if red turns up at the first two throws, what is the probability that
  it is die that is being used?

  我搞不清楚問題再問啥= =

2.consider 10 independent flips of a coin having probability 0.6 of landing
  heads. Say a changover occurs whenever an outcome differs from the one
  preceding it. For instance, if the outcome is HHTHTTTTTT, then there
  is a total of 3 changovers. Find the expected number of changovers.

  我不知該如何下手

3.An ambulance travel back and forth, at a constant speed, along a road
  of length L. At a certain moment of time, an accident occurs at a point
  uniformly distributed on the road. Assuming that the ambulance's
  location at the moment of the accident is also uniformly distributed,
  compute the distribution of its distance from the accident assuming
  independence.




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推 wolf035:第一題是不是貝氏定理??
推 coldtyan:是用貝氏...但還是不知他問的是啥
推 wolf035:問你用的是哪個骰子吧