The average age of a class is $$15.8$$ years. The average age of the boys in the class is $$16.4$$ years while that of the girls is $$15.4$$ years. What is the ratio of boys to girls in the class?
The correct option is B $$2 : 3$$ Let the number of boys and girls in the class be $$x$$ and $$y$$ respectively. Total age of the class $$= 15.8 \times (x + y)$$ $$=(15.8 x + 15.8y)$$ years Total age of the boys $$= 16.4 x$$ years Total age of girls $$= 15.4 y $$ years $$\therefore 16.4x + 15.4y = 15.8 x + 15.8y$$ $$\Rightarrow 16.4 x - 15.8 x = 15.8y -15.4 y$$ $$\Rightarrow 0.6x = 0.4 y $$