The average marks of boys in class is 52 and that of girls is 42 . The average marks of boys and gir

Question

The average marks of boys in class is 52 and that of girls is 42 . The average marks of boys and girls combined is 50 . The percentage of boys in the class is\

Professor PC Thomas Classes · Answer

(a) : Let $x$ and $y$ are number of boys and girls in a class respectively.\ $\frac{52 x+42 y}{x+y}=50 \Rightarrow x=4 y$\ $\Rightarrow \frac{x}{y}=\frac{4}{1}$ and $\frac{x}{x+y}=\frac{4}{5}$\ Required percentage\ $=\frac{x}{x+y} 	imes 100=\frac{4}{5} 	imes 100=80 \%$.\