Exercise is useful not only in preventing depression, but also as a treatment. The following graphs show the percentage of patients with depression in remission when exercise (brisk walking) was used as a treatment. (The control group that engaged in no exercise had 11% of the patients in remission.)

a. Find the slope of the line passing through the two points shown by the voice balloons. Express the slope as a decimal.

b. Use your answer from part (a) to complete this statement: For each minute of brisk walking, the percentage of patients with depression in remission increased by______ %. The rate of change is_________ % per_______ .

Percentage with Depression in Remission 60% 50% 40% 30% 20% 10% Exercise and Percentage of Patients with Depression in Remission 26 42 80 180 Amount of Brisk Walking (minutes) Percentage with Depression in Remission 60% 50% 40% 30% 20% 10% (180, 42) (80, 26) 60 100 140 180 Amount of Brisk Walking (minutes)