Find the average speed of a horse that traveled east for 25km in 4 hours.

The direction the horse travels has nothing to do with its speed but ...

The horse would be traveling 6.25 km/hr

You simply take the overall travel (25km) and divide it by the total time (4hr)

You get 6.25km as your answer, meaning that every hour the horse traveled 6.25km every hour.

4 hours later the horse has reached 25km