AMC 8 2001 Problem 19
AMC8 2001 年第 19 题
行程问题★★★☆☆
Car M traveled at a constant speed for a given time. This is shown by the dashed line. Car N traveled at twice the speed for the same distance. If Car M and Car N's speed and time are shown as solid line, which graph illustrates this?
汽车 M 在给定的时间内以恒定的速度行驶，其速度和时间曲线用虚线所示。汽车 N 以两倍的速度行驶了相同的距离。如果 N 车的速度和时间曲线用实线表示，则下面哪张图表说明了这一点？
正确答案 · Correct Answer
D
解析 · Solution
Solution 1
Since car N has twice the speed, it must be twice as high on the speed axis. Also, since cars M and N travel at the same distance but car N has twice the speed, car N must take half the time. Therefore, line N must be half the size of line M. Since the speeds are constant, both lines are horizontal. Reviewing the graphs, we see that the only one satisfying these conditions is graph .
Since Car N goes at a faster speed than Car M, it will take less time to get to the same destination. Reviewing the graphs, we see that only one graph fits this criteria, graph
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