Question

From a school, 80 boys and 45 girls appeared for a public examination. The average marks obtained by boys is found to be 65 whereas the average marks of girls is 70. What is the average marks of the school?

Answer 1

Number of boys in the school = 80
Average marks of boys = 65
Total marks of 80 boys $=80\times 65=5200$
Number of girls in the school = 45
Mean marks of girls = 70
Total marks of 45 girls $=45\times 70=3150$
Total marks secured by 80 boys and 45 girls
= 5200 + 3150 = 8350
Number of boys and girls who have appeared for exam from the school
= 80 + 45 = 125
$\therefore$ Average marks of school
$=\frac{8350}{125}=66.8$