Final answer:
Jay traveled 9.25 km by walking.
Step-by-step explanation:
To find the distance that Jay traveled walking, we first need to subtract the distances traveled by Jeep and tricycle from the total distance of 28.5 km.
Distance traveled by Jeep: 15.75 km
Distance traveled by tricycle: 3.5 km
Distance traveled walking = Total distance - Distance traveled by Jeep - Distance traveled by tricycle
Distance traveled walking = 28.5 km - 15.75 km - 3.5 km
Therefore, Jay traveled 9.25 km by walking.