In a class of 100 students there are 70 boys whose average marks in a subject are 75
In a class of 100 students there are 70 boys whose average marks in a subject are 75. If the average marks of the complete class is 72, then what is the average of the girls?
- 74
- 65
- 68
- 73
Answer
Number of girls = 100 - 70 = 30
Total marks of 100 students = 100 x 72 = 7200
Total marks of 70 boys = 70 x 75 = 5250
This implies that total marks of 30 girls = 7200 - 5250 = 1950
Therefore, average marks of girls = 1950/30 = 65
The correct option is B.