Multiple choice

The average marks obtained by a class of 60 students is 65. The average marks of half of the students are found to be 85. The average marks of the remaining students is

  1. 35

  2. 45

  3. 55

  4. 65
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Total sum = 60 * 65 = 3900. Sum of first 30 = 30 * 85 = 2550. Sum of remaining 30 = 3900 - 2550 = 1350. Average of remaining = 1350 / 30 = 45.

AI explanation

The total marks of all 60 students is 60 times 65, which equals 3900. The total marks of the first half (30 students) is 30 times 85, which equals 2550. The total marks of the remaining 30 students is 3900 minus 2550, giving 1350. Dividing this sum by 30 gives an average of 45 for the remaining students.

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