Calculating probability from a verbal description

In a math class with 19 students, a test was given the same day that an assignment was due. There were 10 students who passed the test and 14 students who completed the assignment. There were 6 students who passed the test and completed the assignment. What is the probability that a student passed the test? Write your answer as a fraction.

In a math class with 19 students, a test was given the same day that an assignment was due. There were 10 students who passed the test and 14 students who completed the assignment. There were 6 students who passed the test and completed the assignment. What is the probability that a randomly selected student passed the test but did not complete the assignment? Write your answer as a fraction.

In a class 20 of students, 13 have a brother and 5 have a sister. There are 2 students who have a brother and a sister. What is the probability that a student chosen randomly from the class does not have a brother? Write your answer as a fraction.

In a class 20 of students, 13 have a brother and 5 have a sister. There are 2 students who have a brother and a sister. What is the probability that a student chosen randomly from the class has a brother OR has a sister? Write your answer as a fraction.

In a class 22 of students, 15 are upperclassmen and 9 have an A in the class. There are 7 students who are upperclassman and do not have an A in the class. What is the probability that a student is an upperclassman and they have an A? Write your answer as a fraction.

In a class 22 of students, 15 are upperclassmen and 9 have an A in the class. There are 7 students who are upperclassman and do not have an A in the class. What is the probability that a student is an upperclassman OR they have an A? Write your answer as a fraction.