Answer
27 feet (the error is shown below)
Work Step by Step
The student is incorrect with his conversion factor. By writing 3 yards / foot, the student implies that there are 3 yards in a foot. However, there are actually 3 feet in a yard. Thus, we obtain:
$\frac{9 yd}{1} \times \frac{3 feet}{1 yd}=27 ft$
