The average marks of the first 12 students in a class was 33, and the average marks of the next 8 students of the class was 45. What is the average marks of the class? (correct to one decimal place)
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 37.8
Number of students in first group = 12
Average marks of first group = 33
Total marks of first group = 12 × 33 = 396
Number of students in second group = 8
Average marks of second group = 45
Total marks of second group = 8 × 45 = 360
Total students = 12 + 8 = 20
Total marks = 396 + 360 = 756
Average marks of class = 756 ÷ 20 = 37.8