in a class of 55 students, some study at least one of the following subjects; statistics, economics and English. 20 study none of them. The following gives further details of the subjects studied....

in a class of 55 students, some study at least one of the following subjects; statistics, economics and English. 20 study none of them. The following gives further details of the subjects studied. statistics only 4, economics only 5, English only 7, all three subjects 3, statistics and English 7, economics and English 8