Question

一棵树的树顶比另一棵树的树顶高 $16$ 英尺。两棵树的高度之比为 $3:4$ 。较高的树高多少英尺？

The top of one tree is $16$ feet higher than the top of another tree. The heights of the two trees are in the ratio $3:4.$ In feet, how tall is the taller tree?

$\ 48$

$\ 64$

$\ 80$

$\ 96$

$\ 112$

答案：B

知识点：比与比例一次方程

难度评级：900

解答：

设较高和较矮的树高分别为 $b,s$ 。则 $b= s+16$ ，且 $s = 0.75b$ 。代入得 $b = 0.75b + 16 \implies 0.25b = 16$ $\implies b = 64.$

所以正确答案是 B。

Let $b,s$ be the heights of bigger and smaller trees respectively. Then, $b= s+16$ and $s = 0.75b.$ If we substitute, we get $b = 0.75b + 16 \implies 0.25b = 16$ $\implies b = 64.$

Thus, the answer is B .

2010 AMC 8 第 11 题

答案：B

难度评级：900

解答：

其他年份的第 11 题