Question

放学后，玛雅和娜奥米前往 $6$ 英里外的海滩。玛雅骑自行车，娜奥米乘公交车。下图显示了她们的行程，标出了时间和行进距离。娜奥米和玛雅的平均速度相差多少英里每小时？

After school, Maya and Naomi headed to the beach, $6$ miles away. Maya decided to bike while Naomi took a bus. The graph below shows their journeys, indicating the time and distance traveled. What was the difference, in miles per hour, between Naomi’s and Maya’s average speeds?

$6$

$12$

$18$

$20$

$24$

答案：E

知识点：路程、速度与时间数据与图表解读

难度评级：960

小提示：

从图中读出每个人走完 $6$ 英里所用时间

Read each person’s time to travel $6$ miles

大提示：

把 $10$ 分钟和 $30$ 分钟换算成小时

Convert $10$ minutes and $30$ minutes to hours

视频讲解：

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文字解答：

娜奥米用 $10$ 分钟走完 $6$ 英里，平均速度为 $\dfrac{6}{\frac{10}{60}}=36$ 英里每小时。

玛雅用 $30$ 分钟走完 $6$ 英里，平均速度为 $\dfrac{6}{\frac{30}{60}}=12$ 英里每小时。

差为 $36-12=24$ 。

正确答案是 E。

Naomi traveled $6$ miles in $10$ minutes, so her average speed was $\dfrac{6}{\frac{10}{60}}=36$ miles per hour.

Maya traveled $6$ miles in $30$ minutes, so her average speed was $\dfrac{6}{\frac{30}{60}}=12$ miles per hour.

This difference is $36-12=24.$

Thus, the correct answer is E.

2020 AMC 8 第 11 题