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

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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?

posted Nov 11, 2014

+1 vote

the ans was 216mph

+1 vote

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

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

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

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