Q. The average marks obtained by 120 students in an exam is 35. If the average marks obtained by successful students is 39 and the average marks obtained by unsuccessful students is 15 then what is the number of successful students?

A) 80

B) 110

C) 100

D) 90

✔ 100

Additional Information > Exam point of View

The correct option is A 100

Here, total marks obtained by 120 students = 120 × 35 = 4200
Let the number of passed candidates =
Then, total marks obtained by passed candidates = x × 39
And, total marks obtained by failed candidates = (120 - x) × 15
Again, 39x + (120 - x) × 15 = 4200
⇒39x + 1800 - 15x = 4200
⇒ 24x = 2400
∴x=2400/24=100