If the average marks of three sections of Class X, having 35, 40, and 25 students, respectively, are 90, 88, and 80, then the average marks of all the students of Class X, is:
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 86.7
Number of students = 35 + 40 + 25 = 100
Total marks = 35 × 90 + 40 × 88 + 25 × 80 = 3150 + 3520 + 2000 = 8670
Average = 8670 ÷ 100 = 86.7