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A car traveled from A to B in 30 minutes.The first half of t

来源:学生作业帮 编辑:作业帮 分类:英语作业 时间:2024/05/29 12:53:02
A car traveled from A to B in 30 minutes.The first half of the trip was covered at 50 mph,and the second half at 60 mph.What was the average speed?
前一半路程50码 后一半路程60码 可以画一下v-t 图,两个矩形面积相等,可以解得前后两次时间比为6:5,总时间为单位11,则平均v=(50*6 60*5)/11=600/11