Well, let's convert the yards into feet. 1 yard = 3 feet. So Berkley has 10 pieces of ribbon that are each 6 feet, that's a total of 60 feet. 8 * 3 = 24, so she uses a total of 24 feet. Subtract the total amount she used from what she has: 60 - 24 = 36. Berkley has 36 feet of ribbon left.