Hi to all!
I don`t know to do this problems (they are from my last exam), so I would much apriciate if someone can help 
1) Student needs to answer on n independent questions (n is even). Probability that he`ll give the correct answer is P1 for first n/2 questions, and P2 is probability that he`ll give the correct answer for the following questions (n/2). Z is total number of correct answers. Determine the distribution of random variable Z.
2) Donald Duck had hidden $100 bill in one of three books that he currently reads, but he forgot in which one.Pi is the probability that he will find the bill by quickly browsing the i-th book (i = 1,2,3) if the bill really is in that book (it is possible Pi <1).Let`s suppose that Donald Duck quickly browsed through the book and didn`t found the bill. What is the probability that bill really is in that book?
Desperately need help 