There are 100 students in 3 sections A, B and C of a class. The average marks of all the three sections was 84. The average of B and C was 87.5 and the average marks of students in A section was?	Choose the correct choice from the following answers.
A) 20  B) 99  C) 28  D) 27  E) 12
Numbers of students in section A = x   Numbers of students in section B and C = (100 – x)   x 70 + (100 – x) 87.5 = 84 100   70x + 87.5 100 – 87.5x = 8400   8750 – 17.5x = 8400   17.5x = 8750 – 8400 =&gt; x = 20.   20nswer: 20
<result>A</result>
There are 100 students in 3 sections A, B and C of a class. The average marks of all the three sections was 84. The average of B and C was 87.5 and the average marks of students in A section was?