Every student in a certain program of studies takes all three of courses A, B, and C. The average enrollment in the program is 50 students.Past history shows that on the average:
(1) 5 students in course A receive marks of at least 75%.
(2) 7.5 students in course B receive marks of at least 75%.
(3) 6 students in course C receive marks of at least 75%.
(4) 80% of students who receive marks of at least 75% in course A also do so in course B.
(5) 50% of students who receive marks of at least 75% in course B also do so in course C.
(6) 60% of students who receive marks of at least 75% in course C also do so in course A.
(7) 10 students receive marks of at least 75% in one or more of these classes. A sponsor gives a scholarship of $500 to anyone who receives a mark of at least 75% in all three courses. What can the sponsor expect to pay on average?