AMC 8 1990 Problem 17

AMC8 1990 年第 17 题

立体几何★★★☆☆

A straight concrete sidewalk is to be 3 feet wide, 60 feet long, and 3 inches thick. How many cubic yards of concrete must a contractor order for the sidewalk if concrete must be ordered in a whole number of cubic yards?

一条直的混凝土人行道宽 3 英尺、长 60 英尺、厚 3 英寸。如果混凝土必须按整立方码订购，承包商需要为这条人行道订购多少立方码混凝土？

A.2
B.5
C.12
D.20
E. $\text{more than 20}$ / 多于 20

正确答案 · Correct Answer

解析 · Solution

Solution 1

The sidewalk is 1 yard wide, 20 yards long, and

\displaystyle \frac{1}{12}

yard thick, so its volume is

\displaystyle 1\cdot 20\cdot \frac{1}{12} = 1\frac{2}{3}

cubic yards. So 2 cubic yards must be ordered.

继续练习

免费刷 1990 整卷 →