City A lies directly west of city B. When there is no wind, an airliner makes the round trip flight of distance s between them in a flight time of t1 while traveling at the same speed in both directions. When a strong, steady wind is blowing from west to east and the airliner has the same air speed as before, the round trip takes a flight time of t2.

How fast the wind blowing ??

Speed of the wind is

Explanation:

Given that,

airliner cover distance s, in time t1  between the cities faces opposite A and B

Let the speed of the wind be v

and the speed of the plain be

The speed of the plain is

Time taken from one side is

= half distance travelled / (vp +v)

Time taken during A and B is

Time taken during B to A

Total timetaken by plane at the presence of wind

rearrange the equation to get v

Speed of the wind is