To answer 13 you have to convert the numbers there are 8 pints in a gallon so 64/8=8 so there are 8 gallons
For 14 you would do 64x9=576 and there are 12in in a foot so 576/12 so 48 ft and there are 3 feet in a yard so 48/3=16 so Devon need 16 yds of ribbon
