AMC8 2011

AMC8 2011 · Q9

AMC8 2011 · Q9. It mainly tests Averages (mean), Rates (speed).

Carmen takes a long bike ride on a hilly highway. The graph indicates the miles traveled during the time of her ride. What is Carmen's average speed for her entire ride in miles per hour?

卡门在丘陵公路上进行了一次长途骑行。图表显示了她骑行时间的里程数。卡门整个骑行的平均速度是多少英里每小时？

(A) 2 2

(B) 2.5 2.5

(D) 4.5 4.5

(E) 5 5

Answer

Correct choice: (E)

正确答案：（E）

Solution

We observe the graph and see that the shape of the graph does not matter. We only want the total time it took Carmen and the total distance she traveled. Based on the graph, Carmen traveled 35 miles for 7 hours. Therefore, her average speed is $\boxed{\textbf{(E)}\ 5}$

观察图表，图形的形状无关紧要。我们只需知道卡门总共花费的时间和总行驶距离。根据图表，卡门行驶了35英里，用了7小时。因此，她的平均速度为$\boxed{\textbf{(E)}\ 5}$

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