Answer:
2 yards
Explanation:
First find out how many inches are in 1 yard.
1 yard= 36 inches
Now, keep this bit to the side, and multiply the 18 inches and 4 to find how many inches she uses in total.
18 x 4= 72
She uses 72 inches, now you can divide this by how many inches are in a yard which is 36. This will show how many yards of ribbon she uses for 4 boxes.
72/36= 2
She uses 2 yards of ribbon for 4 boxes.