Sandsynlighedsregning - Forskellige spørgsmål til grundlæggende sandsynlighedsopgaver *Engelsk*

Jeg fatter hat af de her sandsynlighedshalløj og kan ikke få hjælp af bøgerne åbenbart.

Første opgave:

The probability that David makes the right decision is 0.6. David always discusses with
John. If John makes the right decision, David will have 0.8 probability of making the right
decision. However, if John makes the wrong decision, David will have 0.7 probability of
making the wrong decision. If Peter makes the right decision, John will have 0.8 probability
of making the right decision. However, if Peter makes the wrong decision, John will have 0.6
probability of making the wrong decision. David’s decision is independent of Peter’s. The
probability that they all make the right decision at the same time is 0.29.
(a) What is the probability that John makes the right decision?
(b) What is the probability that Peter makes the right decision?
(c) If the decision is made by the majority rule of a three-person committee composed of
David, John and Peter, what is the probability of the committee making the right
decision?
(d) If the three-person committee has made the wrong decision, what is the probability that
David has made the wrong decision?

Jeg tror jeg har lavet a og b rigtigt, men hvad skal jeg bruge for at kunne lave c og d?

Jeg gætter på at for at løse opg. c skal jeg finde:

P(at least 2)=P(exactly 2 making correct decision)+P(exactly 3 making correct decision)
Hvor exactly 3 jo er givet:
P(exactly 3 making correct decision)=P(D and J and P)=0.29
Men hvordan jeg så lige finder "exactly 2" kan jeg ikke hitte ud af. Jeg har en opgave, hvor at de alle har samme sandsynlighed p og er uafhængige, men jeg ved ikke, hvordan man gør, hvis de er afhængige på den måde de er.

Poster først opgave 2, hvis der er nogen der hjælper med denne.