What is the helicopter’s average speed over the entire journey?

Question

A helicopter covers its outward journey at 252 mph.

It returns, over exactly the same distance, at 189 mph.

What is the helicopter’s average speed over the entire journey?

Answer 1

the ans was 216mph

Answer 2

Lets assume distance is d then
=> average speed is total distance / total time
=> 2d/(d/252 + d/189)
=> 216

Answer 3

let helicopter covers 252 miles
total distance=252+252=504 miles,
total time=1+1.33=2.33 hour
average speed =total distance/total time
504/2.33=216.31mph

Answer 4

A helicopter covers its outward journey at 252 mph.
And returns, over exactly the same distance, at 189 mph.
so Average speed of helicopter=( 2*252*189)/252+189
=95256/441
=216 mph