Multiple choice

The average marks obtained by 102 students is 18. If average marks of passed student is 21 and that of failed student is 15, what will be the number of failed students?

  1. 51

  2. 49

  3. 50

  4. 52

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Using weighted averages: 102 students × 18 marks = 1836 total. Let f = failed students, then (102-f) passed students contribute 21(102-f) and f failed students contribute 15f. Solving 1836 = 21(102-f) + 15f gives f = 51.