Question

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?

$2$

$5$

$12$

$20$

more than $20$

Answer: A

Concepts:volume unit conversion

Difficulty rating: 1140

Solution:

The thickness is $3$ inches $= \dfrac14$ foot, so the volume is $3 \cdot 60 \cdot \dfrac14 = 45$ cubic feet.

Since $1$ cubic yard $= 27$ cubic feet, this is $\dfrac{45}{27} = 1\dfrac23$ cubic yards. Rounding up to a whole number, the contractor must order $2$ cubic yards.

Thus, the correct answer is A .

1990 AMC 8 Problem 17

Answer: A

Solution:

Problem 17 in Other Years