SOLUTION: a plane flies 450 miles with the wind and 300 miles against the wind in the same length of time. if the speed of the wind is 20 mph, what is the speed of the plane in the air?

Algebra ->  Equations -> SOLUTION: a plane flies 450 miles with the wind and 300 miles against the wind in the same length of time. if the speed of the wind is 20 mph, what is the speed of the plane in the air?       Log On


   

Question 318904: a plane flies 450 miles with the wind and 300 miles against the wind in the same length of time. if the speed of the wind is 20 mph, what is the speed of the plane in the air?
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Let P be the plane speed.
1.%28P%2B20%29t=450
2.%28P-20%29t=300
From eq. 1,
t=450%2F%28P%2B20%29
Substitute in eq. 2,
%28P-20%29%2A%28450%2F%28P%2B20%29%29=300
%28P-20%29%2A45=%28P%2B20%2930
45P-900=30P%2B600
15P=1500
highlight%28P=100%29 mph