IDNLearn.com is committed to providing high-quality answers to your questions. Ask anything and get well-informed, reliable answers from our knowledgeable community members.
first off let's convert the mixed fractions to improper fractions.
[tex]\stackrel{mixed}{3\frac{1}{2}}\implies \cfrac{3\cdot 2+1}{2}\implies \stackrel{improper}{\cfrac{7}{2}} ~\hfill \stackrel{mixed}{1\frac{2}{7}}\implies \cfrac{1\cdot 7+2}{7}\implies \stackrel{improper}{\cfrac{9}{7}}[/tex]
she already did half a hat, so we can say [tex]\cfrac{7}{2}-\cfrac{1}{2}\implies \cfrac{7-1}{2}\implies 3[/tex]
so she only needs enough fabric to make 3 more full hats, we know each one uses 9/7 ft, so
[tex]3\cdot \cfrac{9}{7}\implies \cfrac{27}{7}\implies 3\frac{6}{7}[/tex]