Question 251299
You have too many questions lumped together.

Re-post unanswered questions separately if you want answers.
A man travels from A to B at average speed of 30 miles per hour and returns from B to A along the same route at an average speed of 60 miles per hour. Find the average speed of the entire journey.
rate*time=distance 
The distance AB=BA
In one direction he goes 30 miles and on the return in one hour he goes 90.

In 2 hours he goes 90 miles.
rate *time=distance
r*2=90
r=90/2
r=45 mph