Idon't know how to do it but i at least think it could either be c orme.
sam is testing the effectiveness of a new cough medication. there are 100 people with a cough in the study. thirty patients received the cough medication, and 70 other patients did not receive treatment. seventeen of the patients who received the medication reported no cough at the end of the study. twenty-eight of the patients who did not receive medication reported no cough at the end of the study. what is the probability that a patient chosen at random from this study took the medication, given that they reported no cough?

15%
33%
38%
43%

We could draw a table to help us to answer this question.

                  Took medication         Didn't take medication         Total
No cough               17                                   28                          45
Cough                    13                                   42                          55        
Total                       30                                   70                         100        

The question states "given that they reported no cough", which is basically asking how many people OUT OF those who reported no cough took the medication.

So using the table, the number of people who took the medication and reported no cough is 17. The TOTAL number of people who reported no cough is 45. 17/45 = 37.777 = 38%