2008 AMC 10B 第 12 题

Question

邮差 Pete 有一个计步器来记录步数。计步器最多显示

99999

步，下一步会翻转为

00000

。Pete 计划计算自己一年的里程。一月

1

日，Pete 将计步器设为

00000

。一年中，计步器从

99999

翻到

00000

共四十四次。十二月

31

日，计步器显示

50000

。Pete 每英里走

1800

步。以下哪一项最接近 Pete 这一年走的英里数？

Postman Pete has a pedometer to count his steps. The pedometer records up to

99999

steps, then flips over to

00000

on the next step. Pete plans to determine his mileage for a year. On January

1

Pete sets the pedometer to

00000.

During the year, the pedometer flips from

99999

to

00000

forty-four times. On December

31

the pedometer reads

50000.

Pete takes

1800

steps per mile. Which of the following is closest to the number of miles Pete walked during the year?

2500

3000

3500

4000

4500

答案：A

知识点：位值单位换算估算

难度评级：1070

小提示：

每次翻转代表

100000

步。

Each flip represents

100000

steps

大提示：

总步数为

44\cdot 100000+50000

，再除以

1800

。

Total steps are

44\cdot 100000+50000,

then divide by

1800

解答：

每次翻转计

100000

步，所以 Pete 共走了

44\cdot 100000+50000=4{,}450{,}000

步。

除以

1800

，约为

2472

英里，最接近

2500

。

所以正确答案是 A。

Each flip counts

100000

steps, so Pete took

44\cdot 100000+50000=4{,}450{,}000

steps.

Dividing by

1800

gives about

2472

miles, which is closest to

2500.

Thus, the correct answer is A.

2008 AMC 10B 第 12 题

答案：A

难度评级：1070

小提示：

大提示：

解答：

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