AMC8 2018

AMC8 2018 · Q6

AMC8 2018 · Q6. It mainly tests Averages (mean), Rates (speed).

On a trip to the beach, Anh traveled 50 miles on the highway and 10 miles on a coastal access road. He drove three times as fast on the highway as on the coastal road. If Anh spent 30 minutes driving on the coastal road, how many minutes did his entire trip take?

在去海滩的旅行中，Anh 在高速公路上行驶了50英里，在沿海通道上行驶了10英里。他在高速公路上的速度是沿海道路速度的三倍。如果Anh在沿海道路上行驶了30分钟，整个旅行总共用了多少分钟？

(A) 50 50

(B) 70 70

(D) 90 90

(E) 100 100

Answer

Correct choice: (C)

正确答案：（C）

Solution

Answer (C): Anh’s speed on the coastal road was $20$ miles per hour because he drove $10$ miles in half an hour. This implies that Anh traveled $60$ miles per hour on the highway, and so it took Anh $50$ minutes to drive the $50$ miles. Anh’s entire trip took $30+50=80$ minutes.

答案（C）：Anh 在海岸公路上的速度是每小时 $20$ 英里，因为他半小时行驶了 $10$ 英里。这意味着 Anh 在高速公路上的速度是每小时 $60$ 英里，因此行驶那 $50$ 英里用了 $50$ 分钟。Anh 的整个行程用了 $30+50=80$ 分钟。

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