In a class of 90 students 60% are girls and remaining are boys. Average marks of boys are 63 and that girls are 70. What are the average marks of the whole class?
Answer & explanation
Correct answer: option 3
Number of girls = 90 x \(\frac{3}{5}\) = 54
Number of boys = 90 - 54 = 36
Sum of marks of girls = 54 x 70 = 3780
Sum of marks of boys = 36 x 63 =2268
Total marks = 2268 + 3780 = 6048
Average marks of whole class = \(\frac{d6048}{90}\) = 67.2