Question

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, ten what is the average of the girls?
1. 73
2. 65
3. 68
4. 74

Answer 1

Correct Answer - Option 2 : 65

Total student = 100;

For 70 students total marks = 75 × 70 = 5250

Total average marks of class = 72 x 100 = 7200

⇒ Total marks of girls = 7200 - 5250

= 1950

Average of girls \(= \frac{{1950}}{{30}} = 65\)