AMC8 2005

AMC8 2005 · Q17

AMC8 2005 · Q17. It mainly tests Rates (speed), Coordinate geometry.

The results of a cross-country team's training run are graphed below. Which student has the greatest average speed?

越野队的训练跑结果如下图所示。哪位学生平均速度最快？

(A) Angela Angela

(B) Briana Briana

(D) Debra Debra

(E) Evelyn Evelyn

Answer

Correct choice: (E)

正确答案：（E）

Solution

(E) Evelyn covered more distance in less time than Briana, Debra and Angela, so her average speed is greater than any of their average speeds. Evelyn went almost as far as Carla in less than half the time that it took Carla, so Evelyn’s average speed is also greater than Carla’s.

（E）Evelyn 用比 Briana、Debra 和 Angela 更短的时间走了更远的距离，因此她的平均速度大于她们中任何一个人的平均速度。Evelyn 用不到 Carla 所用时间的一半走了几乎与 Carla 一样远的距离，因此 Evelyn 的平均速度也大于 Carla 的。

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