Solution:
As per the question,
100 = Total number of students
15 = Number of students who passed in English
12 = Number of students who passed in Mathematics
8 = Number of students who passed in Science
6 = Number of students who passed in English and Mathematics
7 = Number of students who passed in Mathematics and Science
4 = Number of students who passed in English and Science
4 = Number of students who passed in all three
U = Let the total number of students
E = Let the number of students passed in English
M = Let the number of students passed in Mathematics
S = Let the number of students passed in Science
As a result, from the above equations, we have,
(i) e = 3 = Number of students in Mathematics only
(ii) a + b + c + d = 4 + 3 + 2 + 0 = 9 = Number of students in more than one subject only