What is the average speed of the coach over the entire journey?

Question

A coach covers its outward journey at 50 mph.

It returns, over exactly the same distance at 33.3333 mph.

What is the average speed of the coach over the entire journey?

Answer 1

40 mph
Assume the distance is 50 miles. The outward journey = 1 hour, the return journey = 1.5 hour.
The total 100 miles is covered in 2.5 hours = 40 mph.

Answer 2

Let the coach journey 50 miles.
the outword journey time =1 hour
coach return same distance time=1.5 hours(time=50/33.33=1.5)
average speed of coach=(50+50)/(1+1.5)=100/2.5=40mph

Answer 3

A coach covers its outward journey at 50 mph.
And returns, over exactly the same distance at 33.3333 mph.
average speed of coach=(2*50*33.3333)/83.3333
=40