Question

A bird is about 6.5 in.​ long, with a​ thin, dark bill and a​ wide, white wing stripe. If the bird can fly 88 mi with the wind in the same time it can fly 72 mi against the wind when the wind speed is 2 ​mph, what is the rate of the bird in still​ air?

Answer 1

20.0 mph

Step-by-step explanation:

Let x represent the speed in still air, and t represent the time of flight;

Speed of wind = 2 mph

When flying with the wind, it's Speed is;

x + 2

When flying against wind, it's speed is;

x - 2

distance = speed × time;

When flying with the wind, distance is;

(x+2)t = 88 .....1

When flying against wind, distance is;

(x-2)t = 72 .......2

Solving the simultaneous equation;

Divide equation 1 by 2

(x+2)t/(x-2)t = 88/72

(x+2)/(x-2) = 1.222

x+2 = 1.222(x-2)

x+2 = 1.222x - 2.444

x(1.222-1) = 2+2.444

x(0.222) = 4.444

x = 4.444/0.222

x = 20.0 mph

the rate of the bird in still​ air is 20.0 mph