2007-II-13

21-06-2023 app.cch 尚無留言

答案：A

\begin{array}{rcl} 7 a + 5 b & = & 3 a + 8 b \\ 4 a & = & 3 b \\ \frac{a}{b} & = & \frac{3}{4} \\ a : b & = & 3 : 4 \end{array}