Answer
a. $0.16$
b. $0.16\%$, $0.16\%$ per minute of brisk walking.
Work Step by Step
a. Using the formula $m=\frac{y_2-y_1}{x_2-x_1}$, we have $m=\frac{42-26}{180-80}=\frac{16}{100}=0.16$
b. For each minute of brisk walking, the percentage increase in remission is given by the value of the slope $0.16\%$. Similarly, the rate of change is also given by the slope in part (a) -- that is, $0.16\%$ per minute of brisk walking.
