Answer :
Answer: 6.375 feet of ribbon will be left unused.
Step-by-step explanation: Given that Ashleigh is making 9 necklaces for cody.
She has 30 feet of string to make the bows and each bow requires [tex]2\dfrac{5}{8}[/tex] feet of ribbon.
We are to find the length of the ribbon that will be left unused.
The length of ribbon required by one bow is [tex]2\dfrac{5}{8}~\textup{feet}.[/tex]
So, length of ribbon required by 9 bows(necklaces) is
[tex]2\dfrac{5}{8}\times9=\dfrac{21}{8}\times9=\dfrac{189}{8}=23.625~\textup{feet}.[/tex]
Therefore, the length of the unused ribbon is
[tex]30-23.625=6.375~\textup{ft}.[/tex]
Thus, 6.375 feet of ribbon will be left unused.