Answer: We want to know the odds against a randomly chosen house having a cat. If you chose a random house, you have a probability of 0.31 of finding a cat there, then you also have a probability of 0.79 for not finding a cat there.
then the odds against selecting a random house with a cat is 0.79, writing it as a ratio we get 79:100, so in 79 of each 100 houses are cat-less.
