Question

The average marks of 120 students in a class is 35. if the average of passed candidates is 39 and that of the failed candidates is 15. find the number of passed students?

Answer 1

Total marks = 120×35= 4200
let the number of passed students be x
therefore number of failed students = 120-x
equation:
39x + 15 (120-x) = 4200
39x + 1800 - 15x = 4200
24x = 2400
Therefore x = 100