Answer:
6 mph
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
[tex]t_{1}=\frac{3}{12}=\frac{1}{4}h[/tex]
[tex]t_{2}=\frac{3}{4}=\frac{3}{4}h[/tex]
total time taken in the 6 miles
[tex]t = t_{1}+t_{2}=\frac{1}{4}+\frac{3}{4}=1 h[/tex]
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
[tex]V_{av}=\frac{6}{1}=6mph[/tex]
