Question

If it takes 6 hours for a plane to travel 720km with a tail wind and 8 hours to make the return trip with a head wind. Find the air speed of the plane and speed of the wind.

Answer 1

The air speed of the plane is 90 km/hr. and the wind has a speed of 15 km/hr.

Explanation:

The plane travels 720 km in 6 hours in the direction of the wind and it takes 8 hours to make the round trip.

If we assume that the speed of the plane is u km/hr. and that of wind is v km/hr.

Therefore, we can write
`u + v = (720)/(6) =120` ........ (1)

And
`u-v = (720)/(8)=90` ..... (2)

If we add those two equations, then 2u = 210, ⇒ u = 105 km/hr.

Again from equation (2), we get v = u - 90 = 105 - 90 = 15 km/hr.

Therefore, the airspeed of the plane is 90 km/hr. and the wind has a speed of 15 km/hr. (Answer)