SOLUTION: It took a plane 50 minutes to fly the 330 kilometers from Washington, D.C. to New York against the wind. The return trip with the wind took 5 minutes less. Find the rate of the p

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Question 946685: It took a plane 50 minutes to fly the 330 kilometers from Washington, D.C. to New York against the wind. The return trip with the wind took 5 minutes less. Find the rate of the plane in still air and the wind speed in kilometers per hour.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
It took a plane 50 minutes to fly the 330 kilometers from Washington, D.C. to New York against the wind.
The return trip with the wind took 5 minutes less.
Find the rate of the plane in still air and the wind speed in kilometers per hour.
:
From the information given we know, it took 45 min to return with the wind.
50 min = 5/6 hr and 45 min = 3/4 hr
:
let s = the plane speed in still air
let w = speed of the wind
then
(s - w) = ground speed to NY
and
(s + w) = ground speed back to DC
:
write distance equation for each way; dist = speed * time
5%2F6(s - w) = 330
3%2F4(s + w) = 330
Get rid of those fractions, multiply the 1st equation by 6/5, the 2nd by 4/3
s - w = 396
s + w = 440
--------------Addition eliminates w, find s
2s = 836
s = 836/2
s = 418 km/h in still air
Find w
415 + w = 440
w = 440 - 418
w = 22 km/h is the speed of the wind
:
;
Use the first original equation to check this out
5%2F6(418 - 22) = 330
5%2F6(396) = 330
You can confirm this for yourself in the 2nd original equation
3%2F4(418 + 22) = 330