1990 AJHSME Problems/Problem 17

Problem

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?

$\text{(A)}\ 2 \qquad \text{(B)}\ 5 \qquad \text{(C)}\ 12 \qquad \text{(D)}\ 20 \qquad \text{(E)}\ \text{more than 20}$

Solution

This is a $1$ yard by $20$ yard by $1/12$ yard sidewalk, so its volume in yards is \[1\times 20\times \frac{1}{12} = 1.\overline{6}.\] Since concrete must be ordered in a whole number of cubic yards, we need $2\rightarrow \boxed{\text{A}}$.

See Also

1990 AJHSME (ProblemsAnswer KeyResources)
Preceded by
Problem 16
Followed by
Problem 18
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