Answer: 1/28 of a spool of ribbon
Step-by-step explanation:
Let x be the part of spool of ribbon used by Mary in each project.
It is given that Mary used 1/7 of a spool of ribbon to complete 4 projects.
So, in 4 projects the part of spool of ribbon is used = [tex]\frac{1}{7}[/tex]
Therefore, in each project the part of spool of ribbon is used = [tex]\frac{1}{7}\div4[/tex]
⇒ In each project the part of spool of ribbon is used = [tex]\frac{1}{7}\times\frac{1}{4}[/tex]
⇒ In each project the part of spool of ribbon is used =[tex]\frac{1}{28}[/tex]
Hence, Mary used 1/28 of a spool of ribbon to complete each project.
