Question

At maximum speed an airplane travels 1720 miles against the wind in 5 hours. Flying with the wind, the plane can travel the same distance in 4 hours.

Let X be the maximum speed of the plane and Y be the speed of the wind. What is the speed of the plane with no wind?

Answer 1

@myko, I have four questions that I need the answers to.

Answer 2

i think @soati is giving you the answer, :)

Answer 3

(X-Y) 5 =1720 That is, the speed of the plane minus the speed of the wind over 5 hours gives you that distance
(X+Y) 4 = 1720 Similar reasoning.

(X-Y)5 = 1720
(X+Y)4 = 1720
Lets solve the first equation first.
You get X - Y = 344 so X = 344 + Y

So we take that and replace X on the second equation by 344 + Y
(344 + Y + Y)4 = 1720
344 + 2Y = 430
2 Y = 86
Y = 43.

Thats the speed of the wind. Now we plug that value of Y on the equation we got for X earlier, resulting in X = 344 + 43 = 387.

So that, 387, is the velocity of the plane without the effect of the wind.

Answer 4

1720/x=5
5x=1720
x=1720/5
x=344 mph against the wind.
1720/y=4
4y=1720
y=1720/4
y=430 mph. with the wind.
(430-344)/2
86/2=43 mph. is the speed of the wind.
344+43=387
430-43=387 mph. speed of the plane in still air.

Answer 5

damn im too late for the partay