In a class of 75 students, 40% are girls and the rest are boys. If the average marks of the girls is 30 and that of the boys is 22, what is the average marks of the whole class?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 25.2
The class average is the total marks of girls and boys divided by 75.
Girls \(=40\%\) of 75 \(=30\); boys \(=75-30=45\)
Total marks of the girls \(=30\times30=900\)
Total marks of the boys \(=45\times22=990\)
\(\displaystyle \text{Average}=\frac{900+990}{75}=\frac{1890}{75}=25.2\)
The average marks of the class is 25.2.