On a multiple choice examination with three possible answers for each of the
five questions, what is the probability that a candidate would get four or more
correct answers just by guessing 10 A person buys a lottery ticket in 50 lotteries, in each of which his chance of
winning a prize is 
1
100 What is the probability that he will win a prize
(a) at least once (b) exactly once (c) at least twice