<PRE><B>Question 920756</B>
In 2hours 30 minutes an airplane travels 600 km against the wind.
 The return trip (with the wind) takes 1 hour 40 minutes.
 Find the speed of the wind and the speed of the airplane in still air.
:
Since we are dealing in km/hr, Convert the given times to hrs
2 hr 30 min = 2.5 hrs
1 hr 40 min = 1{{{2/3}}} hrs (40/60)
:
let s = speed in still air
let w = speed of the wind
then
(s+c) = speed with the wind
and
(s-c) = speed against the wind
:
Write a distance equation for each way
2.5(s - c) = 600
1{{{2/3}}}(s + c) = 600
we can greatly simplify these equations, divide the 1st by 2.5 the 2nd by 1{{{2/3}}} and we have
s - c = 240
s + c = 360
--------------adding eliminates c, find s
2s = 600
s = 300 km/hr in still air
find w
300 + c = 360
c = 60 km/hr is the speed of the wind
:
Check these solutions in the original equations</PRE>