Question

A plane can fly 360 mph in still air. If it can fly 210 miles downwind in the same amount of time it can fly 150 miles upwind, find the velocity of the wind. mph

Answer 1

55 mph

Explanation:

Assuming that

v = velocity of the plane in still air,

w = velocity of the wind.

We are given that v = 360 mi/hr.

Using the equation

x = vt

where

x is the distance an object travels

v is the speed of the object

t is the time taken

While the plane is flying downwind, the velocity becomes v + w. On the other hand, if it is flying upwind, the velocity becomes v - w.

For a particular time t = T, distance traveled x = 210 mi at downwind, and x = 150 mi at upwind.

Creating an equation from the two, we have

210 mi = (360 + w)T

150 mi = (360 - w)T

Solving for T, we have

T = 210/(360 + w)

T = 150/(360 - w)

And since T is the same in both cases, we say that

So, 210/(360 + w) = 150/(360 - w)

Or on rearranging,

(360 + w)/210 = (360 - w)/150

(360)(150) + 150w = (210)(360) - 210w

55800 + 150w = 75600 - 210w

360w = 19800

Therefore, the speed of the wind is 55 mile per hour