Finds how much is needed for 1 costume by dividing 6 3/4 by 3
6 3/4 /3 = 2 1/4 yards per costume.
Multiply yards per costume by 7:
2 1/4 x 7 = 15 3/4 yards total needed.
[tex]\\ \rm\hookrightarrow 6\dfrac{3}{4}yards=3costumes[/tex]
[tex]\\ \rm\hookrightarrow \dfrac{27}{4}\div 3[/tex]
[tex]\\ \rm\hookrightarrow \dfrac{27}{4}\times \dfrac{1}{3}[/tex]
[tex]\\ \rm\hookrightarrow \dfrac{27}{7}yards[/tex]
[tex]\\ \rm\hookrightarrow \dfrac{27}{7}\times 7[/tex]
[tex]\\ \rm\hookrightarrow 27yards[/tex]