Final answer:
The speed of the second person coming from point B is 3 km/h, calculated by using the distance covered by the first person and subtracting it from the total distance between points A and B.
Step-by-step explanation:
Let's find the speed of the second person moving from point B. The first person travels from A at a speed of 4 km/h for 6 hours, which means they cover a distance of 4 km/h × 6 h = 24 km. Given that the total distance between A and B is 42 km, the second person covers the remaining distance, which is 42 km - 24 km = 18 km in the same 6 hours.
To find the speed of the second person, we use the formula for speed:
Speed = Distance ÷ Time
Substituting the known values:
Speed = 18 km ÷ 6 h = 3 km/h
Therefore, the speed of the second person coming from point B is 3 km/h.