Question

为了在他的长方形后院里走一千米（ $1000$ m），Mateen 必须沿着长走 $25$ 次，或者沿着周长走 $10$ 次。Mateen 后院的面积是多少平方米？

In order for Mateen to walk a kilometer ( $1000$ m) in his rectangular backyard, he must walk the length $25$ times or walk its perimeter $10$ times. What is the area of Mateen's backyard in square meters?

$40$

$200$

$400$

$500$

$1000$

答案：C

知识点：周长面积

难度评级：1350

解答：

长为 $1000 \div 25 = 40$ m，周长为 $1000 \div 10 = 100$ m。

周长是长与宽之和的 $2$ 倍。

因此宽为 $100 \div 2 - 40 = 10 \text{ m},$ 面积为 $40 \cdot 10 = 400 \text{ m}^2.$

所以正确答案是 C。

We can see that the length is $1000 \div 25 = 40$ m, and the perimeter is $1000 \div 10 = 100$ m.

Note that the perimeter is $2$ times the sum of the length and width.

This means that the width is $100 \div 2 - 40 = 10 \text{ m},$ and the area is $40 \cdot 10 = 400 \text{ m}^2.$

Thus, C is the correct answer.

2000 AMC 8 第 16 题

答案：C

难度评级：1350

解答：

其他年份的第 16 题