Average speed can be viewed as the rate of change in distance with respect to time. A car traveling at an average speed of 25 miles per hour covers an average distance of 25 miles every hour. So for a horse traveling 25 km in 4 hrs has an average speed of 6.25 km/ hr
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
f(x) = 3x - 1; g(x) = x +4