Incoming students at a certain school take a mathematics placement exam. the possible scores are 1, 2, 3, and 4. from past experience, the school knows that if a particular student’s score is x ∈ {1, 2, 3, 4}, then the student will become a mathematics major with probability x−1 x+3 . suppose that the incoming class had the following scores: 10% of the students scored a 1, 20% of the students scored a 2, 60% scored a 3, and 10% scored a 4. what is the probability that a randomly selected student from the incoming class will become a mathematics major?