Does having pets help reduce the rate of hypertension in adults? To attempt to answer this question, researchers asked a random sample of 50 adults whether or not they have hypertension and how many pets they have (categorized into "none," "only one," or "more than one"). Of the 40 people without hypertension, 45% had only one pet. The same number of people with only one pet and more than one pet had hypertension. And of the 8 people with more than one pet, 75% did not have hypertension.

a) What proportion of adults with at least one pet did not have hypertension

b) are having hypertension and having no pets independent?