SOLUTION: Dear Tutor: I can show you what I have done, because I don't know where to start. I hae 14 problems like this, but maybe if you help me with one I can get the otherones. Flaying

Question 24360: Dear Tutor: I can show you what I have done, because I don't know where to start. I hae 14 problems like this, but maybe if you help me with one I can get the otherones.
Flaying against a heas wind, a plane, could fly 2100km in 6 h, but it would requiere only 5 h for the return trip with the wind. Find the wind speed and the air speed of the plane
Answer by Paul(988) (Show Source):
You can put this solution on YOUR website!
Let the speed of the plane be x
Let the speed of the wind be y

6h ---> the plane flies 2100km with a x speed against a y wind
5h ---> the plane returns with x speed with y wind
against = - . With = +
---> cross multiply.
5x+5y=2100 (1)
6x-6y=2100 (2)
Multiply (1) by 6
Multiply (2) by 5

30x+30y=12600 (ADD) --> eliminate y
30x-30y=10500 (ADD) --> eliminate y
-------------
60x = 23100

x = 385

Plug x into any equation 1 or 2.
5(385)+5y=2100
1925+5y=2100
5y = 175

y = 35

Hence, the speed of the plane is 385mph and the speed of the wind is 35mph.
Paul.