In aclass of 90 students 60% are girls and remaining are boys. Average marks of boys are 63 and that of girls are 70. What are the average marks of the whole class?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 67.2
The number of girls in a class = 90 × 3/5 = 54
The number of boys in a class = 90 – 54 = 36
According to question
The average marks of boys = 63 × 36 = 2268
The average marks of girls = 70 × 54 = 3780
The total marks of boys and girls = (2268 + 3780)
⇒ 6048
The average marks of whole class = (6048/90)
⇒ 67.2