This is a 4-circle Venn Diagram.
Also, point (4) mentions that anyone who follows D must necessarily follow C.
So, D is a subset of C.
The entire Venn Diagram comes out as,
From point (2), let the number of students who follow only A be 2x, the number of students who follow only B be x and the number of students who follow only C be 3x.
Also, from point (3), the number of people who followed all of A, B, C and D = 2x/20 = x/10
Also from point (5), let the number of students who follow only A and B be 3y, the number of students who follow only A and C be 4y, the number of students who follow only C and D be 5y and the number of students who follow only B and C be 6y. Adding the same in the Venn Diagrams, we get:
From point (5)
N
2 + 8 + (N + 1)
2 + 8 + (N + 3)
2 + 8 = 190
N
2 + (N + 1)
2 + (N + 3)
2 = 166
We can either expand the expression and solve the quadratic equation, or we can use hit and trial since we know that N is a natural number.
Solving, we get N = 6,
Hence, the number of students who follow only A, C and D = 44
The number of students who follow only A, B and C = 57
The number of students who follow only B, C and D = 89
Applying them in the Venn Diagram, we get,
We know that the total number of students = 900, Hence,
2x + x + 3x + 0.1x + 3y + 4y + 5y + 6y + 44 + 57 + 89 + 45 = 900
6.1x + 18y = 665 ...(1)
Also, the number of students who are fans of C but not D = 407
Therefore, 4y + 3x + 6y + 57 = 407
3x + 10y = 350 ...(ii)
Solving equation 1 and 2 we get, x = 50 and y = 20
Hence the Venn Diagram comes out as,
Number of students who follow a maximum of 2 clubs = Number of students who follow no club + Number of students who follow one club + Number of students who follow 2 clubs = 45 + 100 + 50 + 150 + 60 + 80 + 100 + 120 = 705
Alternate solution using 4-set Venn Diagram:We can denote the 4-set Venn Diagram as follows:
Also, point (4) mentions that anyone who follows D must necessarily follow C.
From point (2), let the number of students who follow only A be 2x, the number of students who follow only B be x and the number of students who follow only C be 3x.
Also, from point (3), the number of people who followed all of A, B, C and D =
Also from point (5), let the number of students who follow only A and B be 3y, the number of students who follow only A and C be 4y, the number of students who follow only C and D be 5y and the number of students who follow only B and C be 6y. Adding the same in the Venn Diagrams, we get:
From point (5)
N
2 + 8 + (N + 1)
2 + 8 + (N + 3)
2 + 8 = 190
N
2 + (N + 1)
2 + (N + 3)
2 = 166
We can either expand the expression and solve the quadratic equation, or we can use hit and trial since we know that N is a natural number.
Solving, we get N = 6,
Hence, the number of students who follow only A, C and D = 44
The number of students who follow only A, B and C = 57
The number of students who follow only B, C and D = 89
Applying them in the Venn Diagram, we get,
We know that the total number of students = 900, Hence,
2x + x + 3x + 0.1x + 3y+ 4y + 5y + 6y + 44 + 57 + 89 + 45 = 900
6.1x + 18y = 665 .......(i)
Also, the number of students who are fans of C but not D = 407
Therefore, 4y + 3x + 6y + 57 = 407
3x + 10y = 350 .......(ii)
Solving equation 1 and 2 we get, x = 50 and y = 20
Hence the Venn Diagram comes out as,
The number of students who follow only C and D is 100.