The mean of marks secured by 3 students in grade A of class XI is 83, that of 4 students of grade B is 76, and that of 5 students of grade C is 85. What will be the mean of the marks of the students of three grades of Class XI?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. 81.5.
Total marks = 3 × 83 + 4 × 76 + 5 × 85 = 249 + 304 + 425 = 978
Total students = 3 + 4 + 5= 12
Mean =