Question 3
Two chemical substances, A and B, are composed of two basic elements, $x$ and $y$. The ratios of the compositions of the two basic elements in these two substances are $5:3$ and $1:2$, respectively. A new substance C is made by mixing the two substances A and B in the ratio $4:3$. In substance C, what is the ratio of the compositions of $x$ and $y$?