Hello there!
Before you decide which one is a better buy, you have to understand how yard and feet work.
So we know that 1 yard = 3 feet
Thus, 2 yard = 6 feet
Now the question is,
Which is the better buy? A 6 feet piece of linen for $21.60 or a 2 foot piece of linen for $7.02
Thus,
It is better to buy a 2 yard piece of linen for $21.60
Let me know if you have additional question!