Final answer:
The average speed of the horse over the entire journey is calculated by finding the total distance covered (69 meters) and the total time taken (11.6 seconds), resulting in an average speed of 5.95 m/s, which doesn't match the given options.
Step-by-step explanation:
To calculate the average speed of the horse over the entire journey, we need to first find the total distance covered and the total time taken. The horse canters 46 meters away in 9.6 seconds, and then gallops halfway back, which is 23 meters, in 2.0 seconds. Therefore, the total distance covered is the sum of the two distances, which is 46 + 23 = 69 meters. The total time taken is the sum of the two time periods, which is 9.6 + 2.0 = 11.6 seconds.
The average speed is then calculated by dividing the total distance by the total time:
Average speed = Total distance / Total time
= 69 meters / 11.6 seconds
= 5.95 m/s
Since none of the provided options (A) 4.3 m/s, (B) 8.6 m/s, (C) 11.5 m/s, (D) 23.0 m/s match our calculation, there might be an error in the options provided or in the calculations. Based on our calculations, the correct average speed is 5.95 m/s.