A certain bridge is 4,024 feet long. Approximately how many minutes does it take to cross this bridge at a constant speed of 20 miles per hour? (1 mile = 5,280 feet)


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考题讲解

题目分析:

~$4024 feet=\frac{4024}{5280} mile$~所求的时间~$t=\frac{4024}{5280}/20=\frac{4024}{5280*20} h$~

所求的时间为minutes=~$\frac{4024}{5280*20} *60=\frac{4024*3}{5280}=\frac{4024}{1760}=2\frac{504}{1760}≈2.2h≈2h$~

综上:答案就是B

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