The probability that a randomly selected box of a certain type of cereal has a particular prize is 0.4 . Suppose you purchase box after box until you have obtained four of these prizes. (a) What is the probability that you purchase x boxes that do not have the desired prize? h ( x ; 4 , 0.4 ) b ( x ; 4 , 0.4 ) h ( x ; 4 , 4 , 10 ) nb ( x ; 4 , 4 , 10 ) nb ( x ; 4 , 0.4 ) b ( x ; 4 , 4 , 10 ) (b) What is the probability that you purchase six boxes? (Round your answer to four decimal places.) (c) What is the probability that you purchase at most six boxes? (Round your answer to four decimal places.).