statistics: relative frequency from contingency table

[k281127]

A sample of 232 individuals is selected, and the individuals are classified according to their smoking habits and the smoking habits of their parents. The results are given in contingency table below:

contingency table: Parents' smoking habits 
                  Both       Only one   Neither
                  parents    parent     parent
                  smoke      smokes     smokes
  Smokes        |    50    |    19    |   37   |
Does not smoke  |    39    |    43    |   44   |

What is the relative frequency of individuals in the sample who do not smoke?
the answer must be rounded to at least two decimal places.

[FWT]

Do the divsions to find the percentages. Of 232, 50 who have parents that smoke also smoke: 50/232=0.215517 so use 21.55%

Do the others the same way.