Put this into an equation form. You are looking for the number of bows. We will call that "b"
Take the total number of yards of ribbon times the number of yards in each bow and that will give you the number of bows you can make. The equation is
b=20/(2/3)
this gives you just over 30 bows. Round this down to 30 because you can make 30 complete bows with a little extra ribbon left over.