You want to find
; that is, given that you randomly choose from the pool of women, the probability that she does not exercise.
By definition of conditional probability,

496 of the total 1026 people are woman, and 341 of the 1026 people are women and do not exercise, so

A simpler way of doing this is to look at what's called the marginal distribution of women in the table. Basically this comes down to ignoring all but the data pertaining to the women. There's a total of 496 women, and 341 of them do not exercise. So the probability that a given woman does not exercise is 341/496.
Since 25% is 1/4 divide 28 by 4 to get your answer of 9.5
To answer this question you need to add 20 minutes to 5 times 800, which equals 4020, then you divide 4020 by 60 and your answer is 67!