Thread: WORD PROBLEM!

Ok I think this problem is either worded wrong or the answers in the multiple choice are wrong. Or if neither one of those then I'm just lost!

here it is:
An Airliner travels 1432 miles in four hours, flying with the wind. on its return trip, it took five hours flying against the same wind to go 830 miles. how fast would the plane have flown without any wind; i.e. the speed in still air?

a. 81 mph
b. 86 mph
c. 91 mph
d. 96 mph

Any way I plug it in i'm not getting the #'s to work - how do I figure this out??

Originally Posted by Ezra399

Ok I think this problem is either worded wrong or the answers in the multiple choice are wrong. Or if neither one of those then I'm just lost!

here it is:
An Airliner travels 1432 miles in four hours, flying with the wind. on its return trip, it took five hours flying against the same wind to go 830 miles. how fast would the plane have flown without any wind; i.e. the speed in still air?

a. 81 mph
b. 86 mph
c. 91 mph
d. 96 mph

Any way I plug it in i'm not getting the #'s to work - how do I figure this out??

Let speed of plane = x mi/h
let speed of wind = y mi/h

speed of plane with wind = x + y = distance/time = 1432/4 = 358

speed of plane against wind = x - y = 830/5 = 166
so,

x + y = 358 ...................(1)

x - y = 166 .....................(2)
solving these eqns,

x = 262 mi/h = speed of plane

y = 96 mi/h = speed of wind.

Did you get it now ?????

Actually... I have no idea where you got this:

x = 262 mi/h = speed of plane

y = 96 mi/h = speed of wind.

Originally Posted by Ezra399

An Airliner travels 1432 miles in four hours, flying with the wind. on its return trip, it took five hours flying against the same wind to go 830 miles. how fast would the plane have flown without any wind; i.e. the speed in still air?

a. 81 mph
b. 86 mph
c. 91 mph
d. 96 mph

Any way I plug it in i'm not getting the #'s to work - how do I figure this out??

Let the speed Of Airliner=x mph
And speed of wind=y mph

Speed while going with the wind=x+y and speed while going against the wing=x-y

Time taken while going with the wind = 4hrs
Distance=4x+4y=1432
or x+y=358 ----------------[1]


Time taken while going against the wind=5 hrs
Distance=5x-5y=830

or x-y=166..................[2]

Add [1] and [2] to get 2x=524 or x=262 mph.. y=96 mph


OK?

Originally Posted by Ezra399

Actually... I have no idea where you got this:

x = 262 mi/h = speed of plane

y = 96 mi/h = speed of wind.

You have to learn first that "How to solve these equations"

x + y = 358 ...................(1)

x - y = 166 .....................(2)

then, after you can proceed to word-problems. OK ???