Final answer:
Jill's rate of change is -0.7 miles per hour, indicating that she is moving away from the base of the mountain at a constant rate, in the opposite direction compared to someone moving towards the mountain.
Step-by-step explanation:
Jill's hike is modeled by the linear equation d = -0.7t + 3, where d is the distance in miles from the base of the mountain, and t is the time in hours.
a. Jill's rate of change is -0.7 miles per hour.
b. This rate indicates that Jill is moving away from the base of the mountain at a constant rate. The negative sign indicates that she is moving in the opposite direction from Jack, assuming he is hiking towards the mountain since his rate of change is positive.