Multiple choice

The average marks of 20 students is 45. The average marks of the first 10 students is 50 and that of the last 9 students is 40. What is the marks of the eleventh student?

  1. 30

  2. 0

  3. 40

  4. 45

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Total marks of 20 students = 20 × 45 = 900. Sum of first 10 students = 10 × 50 = 500. Sum of last 9 students = 9 × 40 = 360. Marks of eleventh student = Total - (Sum of first 10 + Sum of last 9) = 900 - (500 + 360) = 900 - 860 = 40. Option C matches.

Keep practicing — related questions