First, we need to calculate the perimeter of the bakery.
The perimeter is given by the sum of all sides:
[tex]\begin{gathered} P=2\cdot length+2\cdot width\\ \\ P=2\cdot24+2\cdot15\\ \\ P=48+30\\ \\ P=78\text{ yd} \end{gathered}[/tex]If the cost per yard of the shelf is $6, the total cost will be:
[tex]\begin{gathered} Cost=6\cdot perimeter\\ \\ Cost=6\cdot78\\ \\ Cost=468 \end{gathered}[/tex]Therefore the shelf will cost $468.