SOLUTION: please solve- 2.In a school there are total of 50 students in class X, who are divided in three sections A, B and C. Section A and B have equal no. of students. All the student

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Question 973807: please solve-
2.In a school there are total of 50 students in
class X, who are divided in three sections A, B
and C. Section A and B have equal no. of
students. All the students of the class wrote a
test. The average marks obtained by the
section A and B together is 52.5. The average
marks obtained by the section A and C together
is 60. The average marks obtained by the
section B and C together is 70. The average
marks obtained by the students of sections A,
B and C together is 60. How many Students are
there in Section C.

Answer by JoelSchwartz(130) About Me  (Show Source):
You can put this solution on YOUR website!
A=number of students in section A of class x
B=number of students in section B of class x
C=number of students in section C of class x
A=B
y=total marks for section A
z=total marks for section B
w=total marks for section C
A+B+C=50
2A+C=50
Two times the number of students in section A plus the number of students in section C equals 50 students.
(y+z)/2A=52.5
The total points for section A and B divided by the number of students in section A plus B.
(y+w)/(A+C)=60
(z+w)/(B+C)=70
(y+z+w)/(2A+C)=60
y+z=105A
(105A+w)/(2A+c)=60
2A+C=50
2A=50-C
(105A+w)/50=60
105A+w=3000
w=3000-105A
(y+3000-105A)/(50-A)=60
y+3000-105A=3000-60A
y=45A
45A+z=105A
z=60A
(60A+3000-105A)/(50-A)=70
-45A+3000=3500-70A
25A=500
A=20
40+C=50
C=10
There are ten students in sections C.