There are 6! ways to arrange the hats. The number of ways for which no guest will receive the proper hat is 5! (since there are 5 wrong hats for the first guest, 4 for the second guest, and so on). The probability that no guest will receive the proper hat is:
If two puppies eat 2 cans in two days then you can imagine one puppy eats one and the other puppy eats the other. so if 8 puppies eat in 8 days you would want to do 8 * 8 = 64 cans
