Question

the average of marks obtained by 120 candidates was 35. if the average of passed condidates was 39 and that of failed candidates was 15. what is the number of candidates who passed the examination?

Answer 1

1. Let x be passed students out of 120.Hence 120-x will be failed students
2. Given  the average of passed condidates was 39 and that of failed candidates was 15 i.e, [x(39)+(120-x)(15)]/120=35
3. from this we get value of x= 100 i.e, passed students=100 anf failed students will be 20