contestada

a flyer on a reconnaissance flight has 4 hours for a round trip. his blade can fly 200 mph in still air. he flies out from his base against a 20 mph wind and immediately returns to his base, flying with the same wind. how many hours did he take for his fight out?

Respuesta :

When flying with the wind, the effective plane speed is 200 + 20 = 220 mph.
When flying against the wind, the effective plane speed is 200 - 10 = 180 mph.

Let d =  the distance (miles) from his base to the destination.
The time (hours) to travel with the wind is
t₁ = d/220  
The time (hours) to travel against the wind is
t₂ = d/180

The total time taken is 4 hours, therefore
t₁ + t₂ = 4
d/220 + d/180 = 4
d(1/220 + 1/180) = 4
0.010101d = 4
d = 396 miles

Therefore
t₁ = 396/220 = 1.8 hours = 1 hour, 48 minutes (floght in)
t₂ = 396/180 = 2.2 hours = 2 hours, 12 minutes (flight out)

Answer: 2.2 hours