We have to calculate the average speed if we know the distance and time that Johnatan can jog. The distanece: d = 3 2/5 miles = 3.4 miles. t = 7/8 hour = 0.875 h. Then we will use the formula for the average speed ( velocity ): v = d / t. v = 3.4 m / 0.875 h = 3.866 mph. Answer: The average speed is 3.866 mph.