Answer:
21/8 yards
Explanation:
If Sarah wants to make her own costume she will need 21/8 yards of yarn.
To get this, you multiply 2 by 8 and get 16.
Next, you will add 5 onto 16 and get 21.
Keep your 21 and put is as your numerator.
Now take your 8 and put it as your denominator.