Question

Ara 和 Shea 曾经一样高。此后 Shea 长高了 $20\%$ ，而 Ara 长高的英寸数是 Shea 的一半。Shea 现在高 $60$ 英寸。Ara 现在高多少英寸？

Ara and Shea were once the same height. Since then Shea has grown $20\%$ while Ara has grown half as many inches as Shea. Shea is now $60$ inches tall. How tall, in inches, is Ara now?

$48$

$51$

$52$

$54$

$55$

答案：E

知识点：百分数一次方程

难度评级：1070

解答：

设 Ara 和 Shea 原来的身高为 $x$ 。则 $\begin{align*} 1.2x &= 60 \\ x &= 50. \end{align*}$

Shea 长高了 $10$ 英寸，所以 Ara 长高了 $10 \div 2 = 5$ 英寸，她现在高 $50 + 5 = 55$ 英寸。

所以正确答案是 E。

Let $x$ be Ara and Shea's initial height. Then we get that $\begin{align*} 1.2x &= 60 \\ x &= 50. \end{align*}$

This means that Shea grew $10$ inches, which means that Ara grew $10 \div 2 = 5$ inches, making her $50 + 5 = 55$ inches tall.

Thus, E is the correct answer.

2000 AMC 8 第 10 题

答案：E

难度评级：1070

解答：

其他年份的第 10 题