PSAT Math Multiple-Choice Practice Question 156

Question: 156

A major hospital conducted a study on a new experimental physical therapy method for some of its patients recovering from knee-replacement surgery. At the beginning of the study, 485 patients who had just had knee-replacement surgery were selected for the study; 194 of the patients were given the experimental physical therapy, and the remaining patients were put into conventional physical therapy. A summary of the recovery times for the patients who were in the study is shown in the table below.
Recovery Time for 485 Patients in the Study
Recovery Time
Experimental Therapy
Conventional Therapy
6 months or less
82
151
More than 6 months
112
140

What is the difference, to the nearest whole percent, between the percentage of patients in the experimental physical therapy with a recovery time of more than 6 months and the percentage of patients in the conventional physical therapy who had a recovery time of more than 6 months?

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