Answer: 2 7/16 yards
To find how much ribbon does she have left over you need to subtract the total ribbon with the ribbon used. Since the denominator of the two number is different, you need to find the least common multiple. LCM of 16 and 2 is 16, so the calculation would be:8 1/16 - 5 1/2= 3 1/16 - (1*8)/(2*8) =3 1/16 - 8/16= 2 7/16 yards