Answer:
6 mph
Step-by-step explanation:
Total distance = 6 miles
Speed for the first half that means first 3 miles is 12 mph.
Speed for the next half that means next 3 miles is 4 mph.
Let t1 be the time taken to go for first half and then t2 be the time taken to go second half
By the use of formula for time.
time = distance / speed


total time taken in the 6 miles

Average speed is defined as the ratio of total distance traveled to the total time taken.
So, Average speed in the entire journey is given by
