AMC8 1999

AMC8 1999 · Q7

AMC8 1999 · Q7. It mainly tests Fractions, Ratios in geometry.

The third exit on a highway is located at milepost 40 and the tenth exit is at milepost 160. There is a service center on the highway located three-fourths of the way from the third exit to the tenth exit. At what milepost would you expect to find this service center?

高速公路上的第三个出口位于 40 英里桩，十个出口位于 160 英里桩。服务中心的位于从第三个出口到第十个出口的三分之四处。你期望在哪个英里桩找到这个服务中心？

(A) 90 90

(B) 100 100

(D) 120 120

(E) 130 130

Answer

Correct choice: (E)

正确答案：（E）

Solution

There are $160-40=120$ miles between the third and tenth exits, so the service center is at milepost $40+(3/4)(120) = 40+90=\boxed{\text{(E)}\ 130}$.

第三个和第十个出口之间有 $160-40=120$ 英里，所以服务中心位于英里桩 $40+(3/4)(120) = 40+90=\boxed{\text{(E)}\ 130}$。

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