Question

一个晴天，Ling 决定去山里徒步。她上午 $8$ 点离开家，以每小时 $45$ 英里的恒定速度开车，上午 $10$ 点到达步道入口。徒步 $3$ 小时后，Ling 以每小时 $60$ 英里的恒定速度开车回家。下列哪幅图最能表示整个行程中 Ling 的车与她家的距离？

One sunny day, Ling decided to take a hike in the mountains. She left her house at $8$ a.m., drove at a constant speed of $45$ miles per hour, and arrived at the hiking trail at $10$ a.m. After hiking for $3$ hours, Ling drove home at a constant speed of $60$ miles per hour. Which of the following graphs best illustrates the distance between Ling’s car and her house over the course of her trip?

答案：E

知识点：数据与图表解读路程、速度与时间

难度评级：900

解答：

她以每小时 $45$ 英里的速度开 $2$ 小时，所以步道入口离家 $90$ 英里。图像应在上午 $8$ 点到 $10$ 点之间从 $0$ 英里上升到 $90$ 英里，然后在徒步的 $3$ 小时内保持水平。

她下午 $1$ 点返程，以每小时 $60$ 英里的速度开完 $90$ 英里需要 $1.5$ 小时，所以下午 $2{:}30$ 到家。符合的是选项 E。

正确答案是 E。

She drives $45$ miles per hour for $2$ hours, so the trail is $90$ miles from her house. The graph must rise from $0$ to $90$ miles between $8$ AM and $10$ AM, then stay flat for the $3$ -hour hike.

She starts home at $1$ PM. Driving $90$ miles at $60$ miles per hour takes $1.5$ hours, so she gets home at $2{:}30$ PM. This matches choice E.

Thus, the correct answer is E.

2022 AMC 8 第 10 题

答案：E

难度评级：900

解答：

其他年份的第 10 题