Question

旅行开始时，里程表读数为 $56{,}200$ 英里。司机给油箱加满了 $6$ 加仑汽油。旅途中，当里程表读数为 $56{,}560$ 时，司机又给油箱加了 $12$ 加仑汽油。旅行结束时，司机又加了 $20$ 加仑汽油；此时里程表读数为 $57{,}060$ 。按最接近的十分之一计算，整段旅行中汽车平均每加仑行驶多少英里？

At the beginning of a trip, the mileage odometer read $56{,}200$ miles. The driver filled the gas tank with $6$ gallons of gasoline. During the trip, the driver filled the tank again with $12$ gallons of gasoline when the odometer read $56{,}560.$ At the end of the trip, the driver filled the tank again with $20$ gallons of gasoline; the odometer read $57{,}060.$ To the nearest tenth, what was the car's average miles-per-gallon for the entire trip?

$22.5$

$22.6$

$24.0$

$26.9$

$27.5$

答案：D

知识点：速率

难度评级：1060

解答：

旅行距离是 $57{,}060 - 56{,}200 = 860$ 英里。最初的 $6$ 加仑只是出发前加满油箱；旅途中真正用掉的是后来为补回油量所加的 $12 + 20 = 32$ 加仑。

所以平均值是 $\dfrac{860}{32} \approx 26.9$ 英里每加仑。

所以正确答案是 D。

The trip was $57{,}060 - 56{,}200 = 860$ miles. The initial $6$ gallons only topped off the tank before the trip; the gas actually used during the trip is the $12 + 20 = 32$ gallons later added to replace it.

So the average is $\dfrac{860}{32} \approx 26.9$ miles per gallon.

Thus, the correct answer is D .

1986 AMC 8 第 19 题

答案：D

难度评级：1060

解答：

其他年份的第 19 题