In a class of 60 students there are 20 girls who scored an average of 40 marks in the test, what is the average marks of the boys if the class average is 60 marks?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 70
Total marks of 60 students = 60 × 60
Total marks of 20 girls = 20 × 40
Average marks of boys = (60 × 60 - 20 × 40)/(60 - 20) = 70